To me, the list of mundane equipment is a part of expressing the character's personality. It starts off quite short and generic, and sometimes it grows substantially over time. A few examples:
My first character in the occult WWII campaign was an intrusion and theft specialist. He carried lots of stuff to help with those things, because he often did them alone, and needed all the bonuses he could get. Compiling the list took several hours, a few sessions into the campaign.
My second character in that game is a ritual magician. His equipment list is very short: clothing, a handgun, and a toolbox full of ritual paraphernalia. That's all; he just doesn't feel the need for anything else. He may change his mind, of course, when he doesn't have something he needs in the future.
The last fantasy character I created had a pretty basic list at first, but weight was an issue because encumbrance thresholds are meaningful in GURPS, and he needed to wear a lot of armour. Then in the same scenario ("The Varnhold Vanishing") he acquired a large bag of holding and we had to get a rescued village-full of people back to their homes, thirty or so miles away. That bag now has lots of tents, blankets, food and so on, because he doesn't want to get caught out again.