depends on your target audience and the venue..
pubs/older audience = covers usually go down well
younger audience/proper venue = gotta have your own strong material
no harm is learning a couple of covers and having them ready in case you ever feel you need to pull them out of the bag?
EDIT – to explain to pub comment… in a pub there’s a big chance that 99% of the people there are there to drink and haven’t come along just to see your band play… all the musician’s i know hate it because you will get requests to play certain tracks from drunk people, they will expect to hear songs they know and they’re not usually that polite if they’re not keen on your sound.
if i had paid money to come see you then unless you’ve billed yourself as a cover band then i’d be expecting original material, if you threw a cover in then i’d be hoping for your own bands style twisted into it making it sound fresh and new 🙂