That's about how long I go between topping off my Boge 2.0 cartos. Don't ever believe vendors on how long anything is supposed to last. really depends on how much you hit, and for me if I am
vaping away, yeah, about 30 - 45 minutes. Its LR, so it goes through
juice faster. You probably will get longer from a CE2 carto, but I prefer the excellent vapor and low maintenance of a Boge LR. I use a drip tip, so I just add a few drops when I want. It is likely you are far from drying it out, but the taste can get a bit on the tired side. Realize, however, you are in fact going through the juice faster, so adjust nic levels accordingly...easy to get woozy with a good carto.
There are now XXL 2.5 mL dual coil cartos. Have not tried them yet, but I like the XL ones. And for even more and longer there is the MAP tank, from Clouds of Vapor. Not cheap, but well made and that thing can last you days. But it does sound like your experience with the Boge LRs on an eGo is about right.