Getting up from a table going NO WHERE

So I've been thinking about this for awhile. Ever since I've been multi-tabling, I've had one table run very hot, and the other tables run mediocre at best. What I think I should start employing is a get-up-and-leave strategy if nothing is happening within the first 75-100 hands. What happens is that I will get plenty of action at the hot table, and nothing at the other tables. I think I also need to start watching for changes in table dynamics (players getting up and replaced with new, tighter players). Since I've been multi-tabling, I look for tables with a flop seen % of >30%. I suspect that the tables that I am sitting down to are changing to tighten up. I am going to keep an eye on this in the future.