Hi -
Apologies for barging in like this - I tend to pounce when someone mentions unflavoured liquid!
I have little experience of rebuilding, but I've not had to rewick my rta since setting it up a couple of months ago. I use unflavoured liquid at low power (mtl) and typically get weeks (and weeks) of fairly decent vaping. Same for my drop-in coils. Wish I kept track of how many mls of liquid I'm using, but - well - best intentions and all that. I tend to change coils when nudged by guilt or boredom, and it can be after a couple of months. Even diluting your normal liquid should help longevity.
Oh and @2legsshrt - I see the VT75D here (if you're OK with silver).
Thanks.