As far as upgrading...
For me, I didn't think about upgrading until the setup I was using at the time (Joye -eGo-T and their tank cartridges) didn't seem "satisfying" enough for me. I didn't want to go back to anaolags, so I "moved up" to Vision Spinners and ViVi Nova tanks. About a year after that, I moved up to VAMO's and a Nautilus tank. I tried a few mechs (still like them, and have one or two in my "backup" stash). For the past year, my mod of choice has been the IPV4s, and the Arctic V8 tank.
I've also been able to step down regarding the nic level in my juice. I started at 36mg, but that became too strong for after a few months. I went down to 24mg, then 18, then 12. I'm currently at 6mgs, after vaping for 4 years. I'm hoping to get to 3mg at the end of the year...
Yeah, I remember those old days........I noticed your start date and remembered all the changes this industry has gone through and where it is now... Would not trade my journey for anything as I've been smoke-free 5 and a half years. But those early days were rough sometimes when we were all just learning and getting better. Hopefully, those members starting now won't have to go through so many devices and toppers to get what they are looking for. But, then again, that's half the fun. LOL
I just recently lowered my nic to 3mg from 12mg due to the higher voltage devices. Haven't had any problems what so ever. Well, maybe 1. The 100mg/1000ml bottles in my freezer will now last me 3-4 times longer...oh-vey.