Performance drawbacks

[smbduknow]

Try to implement calendar on nested RecyclerViews (outer RV+LinearLayoutManager hold month items & every month has its own inner RV+GridLayoutManager with its days) and compare performance of both implementation. Your variant with single RV+GridLayoutManager is much slower

[rAseri]

Thanks, it's interesting issue.
On what device did you test calendar performance? Could you share your test app with nested RecyclerViews?

[smbduknow]

I've tested on Samsung Galaxy Note 3 but unfortunately I can't share my implementation at this moment because of NDA. However you can compare your calendar with https://github.com/ApplikeySolutions/CosmoCalendar for example (it based on the same idea)
Try to check case with fast scrolling