Since that's one of the most difficult things in drumming, and we want to practice smart, it would be good to be clear about the real musical need and professional requirement for it; when there are so many important things to work on-- both in music and in life-- to invest as much time as is needed for the more extreme forms of that skill, it had better be pretty useful, or have a big positive effect on other areas of my playing.
Purely as a matter of basic competence, the major circumstance I can think of in which they would be absolutely required would be in an orchestral situation, when rolling on xylophone or timpani (with hard mallets, and/or with higher tunings on the smaller drums). On most other instruments-- any with a long sound-- more reasonably-fast singles will make the required long tone.
Quite a bit more after the break:
On the drums there can be lots of opportunities to play normal-fast singles for short periods-- like four beats or less-- but not so much for blisteringly fast singles for longer than that. Most of the sounds on the drum set are long enough that you don't generally need to play them that fast to have them read as "fast singles", or as a long tone. Slower, they just have more texture. Listen to Paul Motian's solo drum piece Ch'i Energy from Conception Vessel-- his singles here are nobody's idea of fast, but they still don't read as individual notes, they read as a very textured long tone (cue it up to 34:00):
Truly fast singles tend to sound ridiculously fast. And I don't mean that the way some people mean "sick"; I mean they can sound literally ridiculous. Listen to the fill after 0:30:
OK, it sounds really cool to you and me, but I guarantee you that was intended as a musical joke. To your average listener, it's hilariously over the top.
It's not that there isn't a place for them; I think I used them effectively near the end of this piece (cue it up to 3:20 for context if you don't want to listen to the whole thing):
You can hear that they basically render as a long tone (though I don't believe I was playing all that fast), and the same effect could've been achieved with a regular roll, either open or closed. I chose to do it with singles to give an energetic lift to the rest of the band (and to the audience, if there was one) leading into the big ending.
Some final thoughts/conclusions to consider when allocating your practice time:
- Blisteringly fast players have always been something of a rarity, even among the best players.
- There is a big difference in the difficulty and practical value of one beat, two beat, four beat, and open-ended fast singles.
- Playing fast singles and playing fast music are different skills.
- Faster vs. slower singles each provide different, valid musical effects.
- What sounds fast to the listener may not truly be all that fast in drumming terms.