Allocation during rendering loop

IN GENERAL, is it considered to be a bad idea to perform allocations (the “new” keyword) during the rendering loop of a game? Would be be a better idea to pool/recycle objects such as vectors and positions, or keep everything in terms of raw x/y coordinates? Or is the performance gain from all of this not worth the decrease in code simplicity/readability? Especially if I have the intention to someday port a game to Android, where less memory would be available. I realize this is perhaps an overly generalized question but I’m curious as to how many people pursue this kind of optimization.