IMO 10 new levels should be realeased every month may not seem like a lot but it at least igve you challenge of collecting a heck of a lot xp
On a normal week. Averaging 3-4 labs your looking at a level every 10-14 days.
Every 2 months would be fine IMO.
The exp wasted ATM is insane.
Sails chests labs and dbl exp train.