It depends.
Traveling on the scheduled DHs is stress free.
I am relatively stress free on my deviant travel because when things go wrong, I pass that stress on to CRS or the DO. I have missed the 8 hour domestic check-in 4 times now, no issues since I passed that stress on. A bit more stress of will I make it now (and get paid) since the load factors are so high when the travel plans crump.
But losing the pay for one trip isn't that big an issue for me.

The bigger difference is that if you're taking the late, scheduled DH and the connection breaks...CRS will put you in a hotel. Don't make it, you still get paid. Plane's break, CRS and GT fix it.
Deviate-hotel isn't a bankable expense, you work with the airline-and maybe GT to fix it. IF you've got a weeklong pairing, another 300$ fare to get you there is worth it

If you're doing it enough to actually benefit from the FF activity with specific airlines, would say it could be a good idea, depending on where you're trying to go. It sounds like you're probably talking about domestic deadheads.

I think whatever "risk" is inherent in deviating can be mitigated with a good plan. I do it almost every month and the thought of taking a risk doesn't even cross my mind. However, I live near a major hub for two legacy carriers and can get just about anywhere in the US with one flight.

The problem with MEM could be that it's difficult to come up with a "good plan" without jumping through some hoops. Many times you're not one leg away from where you need to be. So, you'll frequently be reliant on getting to an airline hub and connecting (unless your desired destination is the hub). With a limited numbers of flights to make those connections, a cancellation or wx event could really put a wrench in the works.

If you're talking about a Monday morning departure to make a flight that night, you have a pretty tight window before you hit the 8 hour check-in deadline. There's only room for so many back-up options. If you are comfortable with your options, great. If not, you may have to leave Sunday which may not be worth whatever FF benefit you're getting by deviating.

My guess is that you might not be able to make it work every deadhead but it can't hurt to see what your options are and go from there.

I agree with Alderdriver. If you have plenty of backups (particularly direct FedEx jumpseats, not on Mondays), and the weather is good, you are leaving yourself plenty of time, go for it. Who wants to deadhead two legs across the country on Frontier, or an RJ, when you could be sipping wine in first class and getting status on your favorite carrier?

But if the weather is crappy and there aren't many options, don't do it.

In the bad weather months (snow/ice - thunderstorms) I wouldn't deviate on the front end. I'd definitely deviate on the backend if you could get home quicker.

Kronan, what do you mean when you say pass the stress on to scheduling and DO? Sorry, I'm still kinda new.

When you are on a scheduled DH and you miss the connection or the first leg cancels it is not your issue to solve. Sit back, relax, and call scheduling and ask them what they are going to do to get you in position.

Actually, from the context of his reply, I think he's talking about issues that arise while he's deviating. He's just saying he 'fesses up early and gets CRS and/or the DO in the loop rather than keep pushing a bad situation. They either try to salvage things and get him where he needs to be even if he doesn't make the 8 hour limit (likely since a reserve probably won't be any better off starting from scratch in MEM) or they take him off the trip. Either way, it is what it is - stress gone.

Missed the original post. Either way both are good plans. The one where you haven't deviated is totally stress free.

It is also liberating to show them their tight connections sometimes just don't work and watch them scramble to fix it while you sit back and relax. It's not the schedulers fault but it gets dumped in their lap.

Adler is correct,

I usually build my deviation plans such that if I miss my connection there are alternatives to get me there in time to depart, but not necessarily 8 hours prior.

When things go wrong, or things might go wrong (ie delayed departure such that I'm scheduled to arrive 8:01 prior to show) I call CRS.

Scheduling doesn't care, in the slightest, whether you make it there 8 hours prior when you're deviating because the FAA doesn't care what you do to yourself. The 8 hours prior is an FAA required legal rest when the company schedules you, because all company scheduled transportation that's not local in nature is part of your duty day.

So, when things go awry, I call the company. Typically my arrival\final check-in has been in the 7-7:30 prior to my show. Most importantly, I'm not lying about whether I'm in place, and I'm creating the opportunity for the company to make a decision, or start thinking of a backup plan should I not make it. Moving the freight is all the company is concerned with, and if need be they can take me off the trip and do a same duty period DH to a Reserve pilot. Operational JS a pilot into the trip (seen some AM out&backs for Reserve guys to make that happen). Or grab the FedEx biz jet to get a Reserve pilot in position to move the freight.

The absolute worse thing you can do is say you're in position....and then call to say you're not going to make it. Well, the one thing worse might be to call in position and then call in sick 30 minutes prior to show when you realize you won't make it.

I'll make a pitch for calling in honest. A few years ago after the passenger bill of rights law, airlines would just cancel banks of flights rather than face fines for delays when weather got squirrelly. I was trying to go MCO-EWR on a trip when this happened. It was a winter storm and most of NYC was shutting down.

First thing I did when flight was cancelled was check backups, then I called CRS. Kept them in the loop. Decided to go to ATL and try to connect to EWR, JFK, or LGA if it was an option. When I got to ATL...everything from DC to Boston was cancelled. Chatted with duty officer, who pulled me from the trip. I told him I could NOT get to EWR, but since MEM was screaming for help (lots of open time) I did offer that if I could just get to MEM I would fly something for them. DO replied that once pulled from a trip, you could not be put on another except by waiver of ACP. So--I called my ACP, who said "thanks for letting us know, get to MEM, and get to work..."

Point to the story is I kept folks in the loop the whole time, stayed honest, and not only was I not disciplined or chastised but instead still got paid that night. They were drafting that night, but no--I didn't ask for draft--I just said if you will let me fly I'll go to work. And it worked out...

I think the key to deviating is have a back up or two, and if/when those look shaky be honest. I'm sure some EWR local got some draft that night, but the freight moved, the DO did his job, and the schedulers were happy.

Had a similar situation on the 727 years prior with a similar result. Didn't get paid for the trip, but that was all that happened.
No discipline, just an email going "what was your plan?" I had about 4 backups on Delta (to FWA from ECP...small market to small market) but all were weather cancelled with storms across the midwest. Got a reply thanking me for "good headwork" for keeping them in the loop and having a few backups, even if they didn't work that time.

Back in 2014, it was a different environment, and I quit deviating. I had an AA trip to Paris fall through when the MEM-DFW connection was late, and wouldn't allow me to make the turn in DFW. I ended up going First Class on Air France through ATL that night, and it was rather nice. It was also, as pointed out...."stress free" as it was not my problem.

So--deviate or not--you can make it work. Just keep everyone in the loop and shoot straight.