Can I put avocados in the fridge to stop them from over ripening?

I do this all the time. It's hard to keep up with ripe avocados, unless guac is on the menu!

If you know where and how they're grown that probably helps a lot. I don't know, and try as we may to choose 'safe-looking' ones, sometimes they ripen, sometimes they never do, sometimes they're weird inside. We return a few to the store (produce is too expensive to keep if it never ripens, or is weird, or horrible) on occasion. I always ripen them at room temperature and then refrigerate to keep if they're not being eaten immediately. We buy/eat A LOT of avocados.

You sure can. I grew up with 32 avocado trees in my backyard. My mom still lives there. We've always put avocados in the fridge to delay ripening. I still do it when I buy too many to consume. No need to let them ripen first.

Yup. Just make sure they are ripe first...give to a little pressure. Too soon and they get a weird crumbly or greasy texture.