I only have my Da Vinci Just over a week and my refill on the stats is down to 15m, it is still nearly full, but I have been using other colours off standard reels.
The xyz refills are just too expensive, I know form a sales point of view it is clever to make a system that will generate repeat business, but a Da Vinci refill is £34 in UK for 600g, I can buy a 500g ABS Esun reel from HobbyKingUK for £5.61 !!!
Using the same settings (as the stock cartridge is left in place) I also get better quality prints with the Esun ABS, so why when I can get six 500g reels for the price of one refill would I buy from XYZ.
As I still have to make my reset tool, I may be forced to buy one more refill, but if they priced it right e.g. £19.95 then most would probably buy from them to save any hassle, but at that price it is just too much.
Their market is really schools, offices and people who just about can turn the thing on, not guys like us. So we have no choice but to mod them.