A few years back I did a write up on all the various ways I knew of for polyfolk to arrange their bedrooms. At some point, I need to go back and expand it a bit to include sleeping arrangements for solo polies, but aside from that it is still a fairly comprehensive list.
If you’ve been dating a while, you probably have routines for overnight visits. These routines may translate well to living together or they may not. Maybe Erin is fine sharing a bed a few nights a month when Dave comes over, but usually prefers to sleep alone. Maybe Ian can take the couch once a week so Vivian and Carl can share a bed, but he’s not going to be willing to sleep on the couch every night–which means the three of them need to work out sleeping arrangements that will work every night, not just once in a while.
I suggest using that old blog about polyamory sleeping arrangements as a jumping off point for ideas about what your options are and what will work for you and your partners. Things to look at include how (and with whom) everyone prefers to sleep, how many bedrooms you have available, and how big your beds are.
Beds sharing can be a huge jealousy trigger. If Ian and Carl both want to sleep with Vivian, but either don’t have a big enough bed or don’t want to all sleep together, than “who Vivian sleeps with” can become an even bigger issue that “who Vivian has sex with.” After all, everyone has different sex drives, and if Carl is only interested in sex once a week, he probably won’t be bothered by Vivian and Ian having sex twice a week—as long as he and Vivian still have sex once a week. But almost everyone sleeps every night. Carl is used to Vivian sleeping with him most nights, which may leave Ian feeling left out. If Vivian begins splitting her sleep schedule evenly between her partners, Carl will lose a great deal of his regular time with her. Which might cause him to feel abandoned or not cared for.
This kind of thing will play out differently in every relationship. The dynamics will be different in quad than a triad, different when everyone can sleep together, or different when one or more people simply prefer to sleep alone. My first, big, suggestion is to simply talk about it before you move in together. Don’t assume that what had worked for visits will work for every night. Be prepared to be flexible. The first way you try to handle sleeping arrangements doesn’t have to be the only way. If it isn’t working, be prepared to try something else.
Remember that sleeping together is a type of being together, but it does not equal spending time together. The emotional needs that are met by you and your partner(s) get some sleeping together are not the same as the emotional needs that are met by you and your partner spending time together while awake. You probably can’t trade a night spent sleeping together for another date night.