Click here, all the way until the instrumental foundation is laid.
I play piano, bass and guitar, with drums on a recent tune being added by a drummer who got my basic tracks, laid down his work and sent it back. No way I would have him trying to chase me without a solid groove.
When I started working on bass and recording songs 'for real', I thought I was the King of the Groove, no pesky click needed. That changed when I booked the pro drummer on-line.
Then, even with a click, and with me swearing it was in time, the drummer politely pointed out that 'some things were a bit loose'...eye-opener.
Unless you are a loing-time pro player, there is nothing like a click to make you realize how much focus it takes to keep a groove solid yet musical, not just for a 30-sec punch, but for an entire tune at a time. It's the best excercise I know of, and it truly shows your level, good or bad.
C.