When did they start room sharing and how did it go?

We want to put the boys in the same room (our next house is 4 bedroom, but one bedroom is TINY and has no closet). We plan on a third kid, so will bunk the boys together eventually. Their shared room has 2 closets and is big. I'm hoping to do it when DS2 is around 18 months or so (DS1 would be 4).