I use Boge 510 3 ohm (which can also be used on Blu though Blu is not a 510 and Blu's charger will fry a 510)
I can get 10 days or about 15-20ml run through the carto and often more. And the carto still works - it's just degraded enough that I would prefer a new one. I only use thin clear juices - high PG and I avoid all juices that drop flavoring sedment in the stuffing. After using a carto 10 days (which is 3 weeks for me become I alternate
vaping 2 cartos) my carto stuffing still goes white when the carto could use a bit of juice. With a sedimenty juice the carto stuffing will instead turn onto a congealed block of pudding and baked sediment will clog the bottom.