I agree with don't go completely broke getting ME time, but on the other hand it's really hard to get...

I've been a CFI for 3 years and about 1000 dual given, and I'd say at no point in 3 years of instructing have I been drowning in ME time... and I didn't have my first multi student for almost two years.

I know it depends on where you teach, but if someone has a way to get to 50 ME time while working on their ratings I'd highly suggest it. A lot of FBO flight schools don't have a twin, or if they do, private and instrument instruction is their bread and butter and the twin will likely not get rented out a whole lot. The university program that I teach at has a multi course with only 10 hours... and not every student even ends up getting their multi, so I estimate probably only 5% of the total hours flown in our fleet is in one of our twins. But having your 50 multi opens more doors, and if you can't find a good time-building job that gives you multi time, at the very least you meet the 50 hour min for the new ATP cert. A lot (I would say the vast majority) of aerial survey, traffic, jumpers, etc, are being flown in single engine planes.