New to Slot cars

Hi,

My oldest son has recieved a Carrera slot car track as a Christmas gift. I (40M) had forgotten all about slot cars, thought slot cars died a quiet death in the 90s, happy to notice that that's not the case. I'm finding some of the lost teenage enthusiasm with the set and competing with my son.

Anyway, set is already not functioning well, 1 of the cars is acting up and I'm thinking it's the keels. I have a few questions if folks over here might want to answer. I could google this stuff but to be honest, wanted to have conversations with hobbyists about this;

Do keels get worn out?

Is it easy to source keels ?

Is it easy to replace keels?

Are other Carrera slot cars standard, that is, can i buy other cars and use them on my current track?

Thanks a lot.