"Sunday" and "Sundays"

Any difference between the two sentences?

- I usually go shopping on Sunday.
- I usually go shopping on Sundays.

Thank you.

The word "usually" used with the progressive verb indicates that you shop on any Sunday, and not any one particular Sunday so to my mind there is no difference between the two sentences. Personally though I would use the second one.

"Sundays" sounds more generalised.

"Sunday" sounds more immediate like this Sunday.