I'm a street size 10 and just bought a pair of these in size 10. They feel REALLY tight, my toe knuckles are really pressing up through the leather. In reality they hurt. I have a 9.5 in the Anazazi Velcro and while I can deal with them I sized up on these so I wouldn't be so uncomfortable. I've also owned a UFO in 10 which was perfect, but I believe those were unlined so they stretched. Should I size up to a 10.5? Have you ever heard of people sizing up a 1/2 size on these? Or should I wait and allow them to break in? Will they stretch?

Most people go down a half size from their street shoe in the jet.

Stick it out! I am 1/2 size down from street shoe, with a narrow, low volume foot. It took longer than I thought to adjust, but I'm glad I did! But yes, I know many people (those with wide hi-vol feet) who size above street shoe in certain 5.10 models. No, they won't realllly stretch, but they will "morph" to your foot. This always sounds crazy to people, but to break in a TIGHT shoe (and I have done so for years), I climb with socks on for a few outings. Yes, socks with a tight shoe...it actually buffers the hot spots and makes the break-in period more comfy...really....it does. Remember too, this is a performance shoe with a specific mission...not for the slabs shall we say (though as I mention in my review, to my great delight, one can really stand on them when one must-maybe just not the comfy choice.)

I wear a size 10 street shoe and a size 9 in these. They did take about a week to break in, but now I can wear them for at least a couple hours before they start to hurt. Your toes are supposed to be curled up, so I wouldn't worry about that. If you bought them here, you can return them whenever, so wear them for a bit longer and if they don't get better, return them for a bigger size.