Mine went down about 1.5 sizes.
Many will say your feet won't, many also say that they will, up to the gods.
A few tricks though.
If you think a pair of shoes might be half a size too small, buy them anyway.
The first thing to try is the freezer trick.
Get a zip lock bag, put them in the shoes, fill it with water, although I find those garden crystals work better, pop them in the freezer over night, take out, warm up and try on, repeat if needed.
The second is through heat.
Use a hair dryer, warm them up so they're hot to touch, slip them on your feet, keep warming them up again and again. After a while you should be able to get a pair of thin socks on as well, repeat with the socks on.
The 3rd is put them in the dryer for a little bit, you want them again warm to touch, slip them on, use the hair dryer to get them to stretch out a bit more.
Don't wear them out for a few days until you're sure they fit but keep wearing them around the house as much as you can.
If you work at a desk, take them to work as well, all shoes will stretch over time.