How long it takes to learn the drums depends very much on your personal goals. If your goal is to play basic beats and fills, and play along with slow to mid-tempo songs, then just 5-10 minutes of focused practice per day will get you there after a few weeks of playing. Like any musical instrument, you get out what you put in, and your practice time, and the quality of practice will ultimately lead to the fulfillment of your individual goals.
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