I picked up a pair of Lake riding shoes from my dealer yesterday, have not put the clips on just wanted to start breaking them in. Well I wear a 10.5 tennis shoe, and got a 11-11.5 bike shoe and they seem quite tight. How much do these stretch out? If I am going to exchange them for the next larger size I better do it now before they show any signs of use.

Change them out now.

Shoes don't "stretch out" very much...cycling or otherwise. Lake are good shoes...that's what I wear too, but I don't recall them stretching out at all. Also...for sizes, check the Lake website. Mine were in European sizes and I had to match it up for my correct shoe size.

You might want to try Lake's wide widths. And if you want to live dangerously...
find a bike shop nearby that has Sidi Mega Dominators.

Don't look at the price before trying them on.

I like my cycling shoes to be quite a bit tighter than my regular shoes. I dislike having my foot move inside the shoe on upstrokes, and a more snug shoe seems to help make unclipping easier.

Also, I ride Sidi shoes on road and dirt bikes (although not those sweet Dominators!).

I just got some Lakes too. The Kangaroo leather is very supple and nice. Unfortunately, it also seems to scrape fairly easily. I love the BOA closure mechanism. It's very good at putting even closure pressure around the foot no matter what your foot shape.

I also like my shoes to be snug when riding. My road shoes are actually a size smaller than I normally wear. One thing to keep in mind, though, is that while the shoe may not loosen up, your foot may swell on a hotter day. Keep this in mind when sizing.