I'm not asking this as a lazy guy who can't be bothered to do the work, I'm asking this as I genuinely don't have enough time to practice everyday what with working long hours, doing overtime, needing to learn to improve my sight-reading and needing to learn a foreign language (part of the job) on top of that - there simply aren't enough hours in the day for me to practice drums every day. I need to periodize my activities.
So if I can only practice, say, every other day for 20 minutes - will I ever improve? I'm mainly working on hand technique (finger technique) and speed at the moment. If it is possible, what is the most efficient way to do it? Go in speed bursts of 20 seconds or just do long periods at a slow steady speed?
Of course you don't need to practice every day to get better. It's completely dependent on what you want to get out of it. In music's case, how much you put in really is how much you get out.
If you practice every day, even just picking up the sticks at the end of the day before bed for fifteen minutes (and
everyone can do this) and running a few basic single, double and diddle combinations you will see improvement.
If you only had 30 minutes every couple of days to practice, I would focus more on grooves and drum kit stuff rather than technical things. Technical things are great if you have the time to do them, then put them to use in your playing. It's still music we're trying to get better at, not technique. If you
only have 20-30 mins every couple of days to practice, make sure you are practicing playing music. It's easier to kill two birds with one stone and get some technical work in at the kit practicing running singles and doubles around the drumkit (while getting better at fills and fluidity) than it is to practice finger control and then transfer that to the kit later. With a small amount of practice time, you want everything to be focused on getting practical, musical benefits out of it.
For instance: instead of doing finger control on a pad, practice fast sixteenth note funk grooves along to music. You get a great right hand workout and have to incorporate good finger and wrist control into it while gaining great new grooves and musical chops. Add in a bunch of ghost note chatter and you are working your left hand control and speed too! Throw in some killer bass drum combo's and get a good bass drum workout. Play the right hand on the ride cymbal and add in various left foot ostinato variations for independence and four way coordination and you've got a full crazy workout instead of just finger control which will be difficult to transfer to practical use without more time to do it in.
Nonetheless, you will get better. If you practice, you will get better whether it's five/ten/fifteen/twenty minutes every couple of days or six hours every day...if you put in work you will get better.
Edit: Working on stuff like Igoe's G.E in the funk/RnB section would be a good way to go. Sight Reading, technique, grooves, coordination and most importantly, you are playing music the whole time and improving your time.