None.
I ought to explain that. XD As much as I like to obsess over inventory in PC games, in D&D I prefer to spend as little time as possible on figuring out: weights, slots, encumbrance etc etc.
So I simply tell all my players, I will let you run around and carry a reasonable amount of items, and I will consider your stature and strength a bit of course. If at any point I feel the party or PC is carrying a bit too much/not realistic I will ask you to buy a horse, or maybe one each (good way to relieve players of some GP) or to bury part of your treasure or for you to come up with a clever idea to haul all the stuff back to town to sell or store.
If players want to collect more and more stuff, cool! Can be fun. But the party will at one point have to build, rent or buy a base or storage and I will assume that you store everything there, that is not on your sheet (separate single sheet for entire party tracks stuff stored in the base) and reasonable to have as Every Day Carry items for your class/your specific character and personality.
Of course I factor the above in when they find treasure. If I want them to be able to haul stuff easily, perhaps they encounter a man with a cart at the road side they can pay a bit, or they found only PP,… if I want make them think, I will have them find a mountain of CP and/or bulky/heavy items valuable stuff and ask them how to hide or haul it or which spells they want to use to facilitate transport.
Basically if it adds to roleplaying opportunities or fun, induces creativity, might result in side-treks or hiring NPCs or buying services or goods, or if it makes the players think, I will consider encumbrance and let players know they need to take action. But, If they are carrying reasonable amount (and they learn to do this quickly) I prefer not to spend precious session time on encumbrance and on sorta “min-maxing”, bookkeeping and tracking stuff. It is not the most enjoyable aspect of DnD to me and my players, it reminds me a bit too much of PC games. Exploration, roleplaying, collaborative story-telling and world-building, for me personally that is all more fun than encumbrance tracking.