So I think the most stable is native and the most unstable is pop and or push.
How stable is adult banner traffic? Do campaigns usually last atleast a few weeks after optimization?
if you take it adult display vs push or pop, ohh yes.
campaigns can last for more than a few months if you know what you are doing.
It's hard to make a general statement, but yes, I agree with adultyaffiliate, it's more stable than push or pops.
I've created 100s and 100s of adult campaigns during the past couple years, some of them died within a few days, some would last for weeks and I also had some campaigns that were running for months. Depends on the offer a lot too, if it's a solid one, it helps a lot.