From Narita arrival to airport bus limo

Hello,
I am looking into buying the airport limousine bus transfer to my hotel. I need to select the departure hour, but I am unsure of how much time I should allocate from plane arrival to bus departure. Can somebody tell me how much it took in their travel? And yes, I am arrival during cherry blossoms, so I guess it is important to factor that in. Thanks !

Buy your ticket in Narita. You cannot control flight delays or potentially arriving earlier.

Yes, you right. Why give myself extra stress. Thanks.