Let me add my thoughts to some very good ideas already mentioned. It slows me down. It makes me think about what I'm doing. It improves my photography. No chimping here. It creates anticipation waiting for the developing negatives and chromes to come back from the processor. (I don't have nor want a darkroom. There's no space anyway). It hasn't gotten boring. It's nice to handle and use the old MF equipment.
When you finally scan it and post it on line or print it (rarely right now), you have a feeling of accomplishment. Here's one I just posted. It took over a month from the time I shot it until now. Film teaches patience. http://www.flickr.com/photos/alanklein2000/11021823226/