I heard an interesting drummer one night. He had good chops, good ideas, and served the music well. He also kept messing up the time. Few things make me sadder than hearing an otherwise capable musician who is in dire need of some metronome practice.
I know what some of you are going to say: Practicing with a metronome will mess up your natural timing. I have only one thing to say to that. I've never been faulted for keeping good time.
When I was at jazz school, I landed a gig alongside a bass player whose time was wretched (but the job paid well and had other perks). About a month after starting this gig, my ensemble professor pointed out that my time was, uh, messed up*. He concurred that playing with someone who has bad time can seriously mess with your sense of time. Fortunately it's not a permanent condition. In contrast, playing with people with solid time will also improve your sense of time. And, what could provide a more solid partner than a metronome?
The key to working with a metronome is to focus on the metronome. Too often we start the metronome and then turn our attention to the exercise. You need to listen to the beat of metronome and then put your strokes exactly where they belong. A real torture test is to play on a hard surface. You can't fudge this one.
Slow & Steady
Practicing slow tempos will help with slow tempos. No surprise there. A tendency to speed up is bound to show up at 40 bpm. Slow practice also gives you time to really focus on what you're doing.
Pedal to the Metal
The metronome is helpful in regulating faster tempos and also with speed development. To play a fast jazz ride at 300, just set your metronome at 300. To play faster still, bump the metronome up from time to time (also see http://drumyoda.blogspot.com/2013/02/faster-faster.html).
Inside Story
One of the best exercises I've seen for really nailing things down is to put the click 'inside the beat'. If the exercise is 8th-note based, count the clicks on the '&'. For swing or shuffle, set the metronome on the skip beat, as in 1-trip-LET. For a real challenge, have the click represent 'e' or 'a' or the middle triplet. I find these fun to do and not that difficult. Mark Kelso's DVD has an excellent overview of this (https://www.groovydrums.com/musician-first-drummer-second/.)
Spatial Perception
Another great challenge is to spread out the clicks. Begin with the click on all four beats, then on 1 and 3. Then let it be just on 1. Then let the click be the first beat of a two-bar phrase.
Just One of the Gang
People in the know (e.g. Bernard Purdie, Gavin Harrison, etc., etc.) treat the metronome or click track as just another member of the rhythm section. That should be your goal -- let the metronome be the clave to your samba.
BTW, I recommend spending no more than half of your practice time with a metronome (and only for the first 10 or 15 years). And don't worry. The music will 'breathe' just fine despite your excellent time.
* I heard a better one at a big band practice. The leader called out one of the trumpet players and said, “You're time's sort of all shot to hell”.