I keep a few long running chats for important things and then just keep the random questions as individual chats. There's not a lot of structure but it works.
For example at the moment I have 1 long chat about some health stuff, 1 long chat about some bicycle repairs I'm doing, and then the rest are one offs. I rename the long ones (or just remember the name) and they stay at the top because I find them when I need.
I also manage memories assertively. If there's something important that I'm tired of repeating I just ask it to add it to memory and it will do it.
Most of my professional work is done in cursor so it's in a different place to my personal questions. These usually are one chat per feature kind of thing, and start a new one when it gets confused with the enormous context