15 years of experience
Having been in a partnership with the same person on 3 boats over 15 years here is my 2 cents. Discuss ahead of time, usage together and seperate, overnight stays, holiday usage, maintenance, upgrades, finances, will one race and the other not. I found the biggest problems were in the level of preventative and regular maintenance (checking oil and batteries, washing before going out, cleaning interior, spider maintenance, etc) Another cause of aggravation is individual usage on holidays or overnite trips. We drafted an agreement to cover much of the above but we ended up not really following it and working out differences as we go along. It does teach one to be flexible though. We piss and moan at each other but still laugh and continue. Good Luck