I compose and record almost exclusively through a pair of Shure headphones, because using my speakers tends to upset the neighbours unless I do so at very low volumes. I live in an apartment with neighbours both above, below and next door, and so playing music at a loud volume would be considered antisocial behaviour, and the walls are paper thin.

Obviously percussive and acoustic instruments, vocals or any mic'd-up guitars are going to be heard, but I try to record those at more social hours. I have a lot of world percussion stuff, and my congas in particular are kind of loud.

The main issue is that using the cans for too long gives me 'dead ear' - my ears literally become deadened to the extent that I can no longer detect the various nuances within the song. This requires stepping away from the studio for a few hours to get things back to normal.

I've no choice but to switch to speakers when actually balancing and mastering the thing as cans give a false sense of depth, though they're good for monitoring stereo balance.

I don't use a bass amp at all - I use direct input through a tube pre-amp, and virtual amps (generally Vintage Amp Room) take the place of a bass amp, and once I've got everything properly filtered, limited, compressed etc. I find that an amp isn't really necessary. Guitars are a bit more of a problem and often the amp is the only really valid solution - but it really depends on the song.