When referring to checking the weather at alternate that is true that you are required to check wx and change the alternate if the weather goes below mins. It is hard to do in a non-ACARS aircraft and it depends on whether you have a good dispatcher or not. I guess I was trying to say start looking at other airports in addition to your alternate if weather is marginal at your destination. In regards to the 123 rule you got me on that one, (semantics) but I think everyone got the gist of the conversation.