I always fish relatively shallow for bluegill even through the heat of the summer. Plenty of them do go deep, but I prefer fishing shallow with a float (the thrill of bobber watching is addicting to me) and can often find schools of them on flats where the water is 4 - 8 feet deep no matter the heat. Sometimes I need to set the float to about 5 feet, but that is the deepest I'll generally fish a float (I'm no good at slip float techniques). I do like to swim small jigs without a float just off the bottom when fishing without the family as that adds significantly to the possibility of catching some nice shellcrackers. When desperate though, I will resort to drop shotting a cricket or wax worm along drop offs, but only resort to that if I have a few in the cooler and it doesn't look like I'll get enough for a family meal. For pure catching I haven't found anything better, but I find my enjoyment in watching the cork tingle with anticipation before going under.