I had a client who had a usage frequency similar to AirBnB (one or two transactions a year) but then tried to cross-sell meal tickets (one or two transactions a week) because VCs were telling them users were not "using the app enough".

The meal ticket experiment turn out to be an expensive mistake - users never used the feature again after the promo period. From a retention perspective they didn't lose anyone, but the blended CAC for that quarter was horrible.

In hindsight, I think the practice of comparing retention between companies is doing more harm than good.

If your retention rate tells you you are providing a "one-off" service - that's OK. You just have to focus on being a cost-efficient service provider instead of splurging on CAC like everyone else.