we started out with personal current and savings accounts and a joint current account, salaries went into our own accounts and we transferred agreed amounts to handle bills and living expenses into the joint account. As time passed it just seemed to be a bit of a pain. First step was moving salaries to the joint current account, after a while we closed our personal current accounts. More recently we've setup joint savings/investment stuff and closed down the personal ones in that vein.
This was partly fuelled by the fact that we have everything accessible online but that bit is left to me. So I could login and see Janes state of play any time I liked but she didn't have similar access to my info. But the biggest factor was if something happened to one of us. I've handled probate for friends/family a few times over the years and life is easier if things are in joint names. Being me I've also prepared written instructions re what needs to be done that either Jane or the boys could follow with ease.
Anything else is really down to trust and personal attitudes, no-one else can make that decision for you, the above is just what works for us but has been over 20 years in evolving to this point.