Personally I don't have room for anything except plants. When I enlarge , or rebuild - or extend - currently I am doing that for the 20th (?) time I get back to a potting bench and a stores area, but they soon get swamped.
I do have a good utility room next to my kitchen with a fine large sink with hot and cold water and a good draining board, all stainless steel , and I sometime bring a bucketful of pots there to wash and sterilise - but more often than not just put a bucket on the greenhouse steps ( my main greenhouse is a pit house , floor 3 feet below ground level) and use that as my bench.