I have to keep them small or I can't keep them all.
I posted photos in [url=https://www.helpfulgardener.com/forum/viewtopic.php?p=173115#173115]this post[/url] in Dec. '10. They are bigger by about 12 inches each now but are still able to stay in front of the same window.
Key and where most people fail IMHO is to provide plenty of light while they are inside
to prevent spindly, leggy growth. Aim for short internodes (lengths of stem between leaves). When taking them outside for the summer, be sure to gradually acclimate them and eventually move them to a location with noonday shade but good morning sun and short amount of afternoon sun -- as much as your plants can take. Avocados sunburn easily.
Edit: Haha. If as Gary says, they grow fast to 7-8ft in full sun, then I guess it's a good thing I'm keeping them on a diet. I wouldn't be able to being them back inside then.