Upgrading gear while leveling

Hello,this is my first discussion post on this forum. I would like some advice on gearing while leveling and whether i should do it or not. So i'll just say a couple things about myself i guess. First,i have a bad habit of killing too much stuff while running around and getting overleveled (had that habit since d2 and titan quest). I'm managing to keep it tighter now,with having a simple mission for each map - go do the quest of the map and on my way do the ultimatum,thats it(but i still throw out aoe's while running,so i guess that's what gets me overleveled),BUT i love the leveling part and am not in a complete rush to 'endgame',as i'm trying out new builds. Next thing is.. i probably pick up too much stuff. So i have a filter setup to semi strict or whatever its called,where it shows a bit more blues and stuff. I know it's considered a waste of time to pick them up and vendor them,but let me explain.. So i'm counting alts as 3 or 3.5 to 1chaos,which is easily tradeable on a constant basis. And vendoring all blues and rares(also identifying them to get alt shards and not trans shards) nets at least 0.7-2c worth of currency each vendor trip. Thats pretty much how i get all the gear. So now to the gearing while leveling part. I have the unique 'set' of leveling items (tabula,wanderlust,lochtonial etc.),and some upgrades that i equip down the line while leveling up (strength spikes at like lvl 10-12 and 20+,30+). So here's my questions,sorry for this long story... 1. Is say.. 1-2c worth of 1 trip to vendor(with tele gem,so i dont waste any scrolls) worth it? Keep in mind,this is 1-2c while being like..lvl30-50,so used for gear,which brings me to my second question.. 2. When should i upgrade my gear? Like in what intervals? Let's say im lvl50 in lvl 35-40gear,max resists,clearing instantly or almost instantly,and easily dealing with uniques/bosses. So at what point should i upgrade? Only when i start struggling/almost dying? Or,like i do it(this is also where i want advice if this is wrong to do), check the poe.trade for upgrades to get closer to my 'build guide goals'. Maybe unique items can carry me to mapping and such,and only then i should upgrade? Thank you everyone for your attention.

You're overthinking this.

It's leveling. Just get through it how ever you can. It's less than 5% of your character's play time.

While leveling, you just care about resistances, life, and sockets. Except for your weapon, and dps mods there depend on your build. (Ok, movement speed on boots too...)

If you use a filter and get good spotting things, a decent build can get to at least yellow maps on totally SSF gear and no effort. (Maybe buying a 5L or corrupted 6L if you don't have a tabula.)

Ok,so what im getting is,get to leveling,keep defences at max,other items will come. So i guess only trade for items if i dont get anything good to drop,or if the build guide im following specifically requires this or that? But the question about vendoring is still there i guess.. right now,by vendoring the blues the filter shows+all the rares i dont need,i get around 100-150c worth of orbs a day,to trade in later. Do i keep doing this (i enjoy it a bit LOL,but if its insanely bad for me,im willing to drop it/limit it),or just get to maps asap and start getting currency there? TY

Vendoring stuff is more important on your league starter. You will want trans and alts for things like flask and bench crafting. Chance for Zana maps. Use your filter to flag linked RGB items for chromis and 6s items for jewellers.

At some point it becomes less important. Just depends how you like to play.

Well i guess i got my answers,thank you :)