depends, when i was just diving on vacation i started with renting everything. then i bought a well fitting mask from my local dive shop and a computer. a rashguard to wear under rented wetsuits. i was gonna buy a hood and maybe another layer to bring with me as i get cold easily and the tropical destinations mostly had shorties. i didn’t see any need owning much else when just diving on vacation a couple of times a year, seemed like more of a hassle to lug around more stuff.
now that i’m diving locally, well, you kinda have to own everything, but i don’t own tanks (yet)