First thing I learned when we started vaping, even before I discovered ECF. We were using cigalikes with cartos at the time, and had issues with the charging packs and batteries. I always made sure we had a few extra batteries, chargers and cartos. Still have them, just in case everything else fails. We were able to set up my daughter's boyfriend's grandfather when he decided he wanted to try vaping and insisted on something that looked like a cigarette, with the provision that if he decided not to vape the equipment would be returned or given to someone else and not thrown out. We got the equipment back, and has not told the boyfriend what he did not like. I would love to talk to Grandpa to see if we can find out what the issue was, and maybe get him set up with something that will work for him.
When we moved on to Evods, I was able to order 2 starter kits each for my daughter and myself, along with a Protank 2 Mini for each of us, so that we each had 4 batteries, 4 Evod tanks, and a Protank 2 Mini. We have had batteries fail, tanks melt or get dropped onto cement, etc., and still did not have to worry - we had spares, and I made sure to replace each item that failed as soon as I could. Those are our main backups, and I have enough spares of everything to set someone up if they want to try vaping, and still not worry if our main equipment fails.
My daughter is now using an Innokin VV v3 with a Nautilus Mini. I am currently using a CoolFire IV with either a Nautilus Mini or an Evod Glass tank (I am planning to order myself another Nautilus Mini in a week or two). The boyfriend is now using a Kanger Subox Mini kit with the sub-ohm coils.
We are on a tight budget and most of the vape budget comes out of my Social Security check after my share of rent and bills are taken care of. We upgrade/order spare parts, etc., as and when the budget allows (except for coils and eliquids - those are in the monthly budget). Thank the Goddess Nicotina that we have a local vape shop with knowledgeable employees and prices that are comparable to online vendors that we can turn to in case of emergency.