Hi Ksenia!
at this point, the kids start out the night in bunk beds in their own room, but 99% of the time, when they get up to pee, they come in with us. Occasionally Lucy,7, will still be sleeping in her own bed by morning, but not usually.
when they were younger, we had a queen size bed with a twin bunk next to it, so Lucy could sleep up top, dexter had the bottom bunk, and mark and I had the queen...or mark had the top bunk, the kids and I all had the queen, or any other number of combinations.
When we move, Lucy wants her own room, so I think we'll put a queen in her room to serve as a guest bed from time to time, and we'll put the bunk bed in dexter's room, and he'll usually sleep on the bottom, but if we have guests, lucy can sleep in the bunk bed with him, or they can both come in to our king size bed and guests can have both the kids' rooms... it seems like a versatile set up, but who knows where we will actually all end up every night! Actually, I do know where we will all end up sleeping, which is why we invested in a king size bed *after* the kids had their own room!
happy restructuring!