We, as climbers have been told for years that your climbing shoes need to be painfully tight for the perfect fit so that we can be awesome at rock climbing. A well form fitted climbing shoe may improve one's climbing but a overly tight painful fit can cause problems long term. This could actually be harming your feet more than you think especially if you have already pre-existing conditions. Here are some of the conditions that can be caused by wearing too tight of footwear:
Hammertoes: a contraction or bending of the joints on one or multiple toes. Hammertoes can form if the toes are too long and are forced into a cramped position when a tight shoe is worn. While hammertoes are flexible and can be treated but if left untreated can lead to a surgical situation.
Bunions: I used to only think old people (no offense!) got these, but they can happen to young and old alike. A bunion is when your big toe joint becomes enlarged an crowds against your other toes. The force from your big toe then forces the bone outward as shown in the photo. A bunion can develops from the pressure on the foot when force into tight narrow pointed shoes, which is basically what climbing shoes do.
Ingrown toenails: These are one of the most gruesome and possibly dangerous of toe problems. An ingrown toenail can be caused by constant pressure placed on the toenail, which then causes it to dig and cut into the skin. Many times this can lead to a puss filled infection that can pop like a stepped on Boston Creme doughnut!
The next time you jam your little piggies into your overly tight climbing shoe, remember you can be causing your feet more problems than the number of sends that day. While wearing your climbing shoes, keep your feet snug, pain free, and give 'em a break between tries. And for the sake of everyone's nostrils, keep your feet clean and stink free!
Some images used from: http://www.foothealthfacts.org