Well, I usually only play 4 tables or so on average, so its easier for me to be picky. But this is definitely something you should be thinking about anyways. Especially if you start opening up your game a bit at times, you need to know when to tighten back up. Most of the time its probably still worth keeping the table open, if there arent many to chose from. Maybe jump on a few waiting lists if it seems marginal.