Daily is the best if your way is think deeply the chess, but in short matches I prefer Blitz 15 min.
What time control is the best?


Yes... some help please. Given a limited amount of study, which of the following will best improve ones game?
Fast blitz.
Slow blitz.
Rapid.
Or some combination of those?
According to many people, rapid is best.
However, if it's slow enough you can play slow blitz liike me.

You learn more on slow time controls, but blitz gives you more experience since you can play more matches of blitz.

I like Rapid 30 minutes. It gives you time to think and plan, but doesn't take too much of your time.

I don't know if there is any "best." Why limit yourself though? If you want to be a solid chess player, then you shouldn't condition yourself to a particular time control - rather you should be able to adapt fairly easily and play the chess position itself. Personally, I can't play bullet well at all and even blitz is too fast for me at times, but I think that a little bit of bullet/blitz can help (not hurt!) IF done correctly. The "IF" is important here. What you shouldn't do is get addicted to moving without calculation and avoid reviewing the games.
Long time controls gives you good practice for calculation, blitz/bullet gives you good practice with pattern recognition and rapid is a balance of both; I say you should experiment with many different time controls
"... One thing I noticed quite clearly is that weaker players who primarily play intermediate time limits online develop very bad analytical and time management habits. ... many Internet playing servers rate fifteen minute games as standard (slow) … in a fifteen minute game, players have an average of about twenty-two seconds to make a move. … What rating would [you] have to be before you can even determine if a move is good in twenty-two seconds, much less look for a better one? ... a player has to be fairly high rated to accurately make this type of determination that fast. Most weaker players don't have sufficient board and tactical vision to determine all the safety issues so quickly, much less resolve the additional issues that would correctly identify a move as 'good.' ..." - NM Dan Heisman (2010)
https://web.archive.org/web/20140627030447/http://www.chesscafe.com/text/heisman115.pdf
"... Most internet players think that 30 5 is slow, but that is unlikely slow enough to play 'real' chess. You need a game slow enough so that for most of the game you have time to consider all your candidate moves as well as your opponent’s possible replies that at least include his checks, captures, and serious threats, to make sure you can meet all of them. For the average OTB player G/90 is about the fastest, which might be roughly 60 10 online, where there is some delay. But there is no absolute; some people think faster than others and others can play real chess faster because of experience. Many internet players are reluctant to play slower than 30 5 so you might have to settle for that as a 'slow' game." - NM Dan Heisman (2002)
https://web.archive.org/web/20140627010008/http://www.chesscafe.com/text/heisman12.pdf
"... I would guess up to ninety percent of your playing time should be slow games (thirty minutes for each player or preferably more) and the other ten percent speed games. ..." - NM Dan Heisman (2009)
https://web.archive.org/web/20140627020325/http://www.chesscafe.com/text/heisman100.pdf

So how come these master dudes telling us patzers to play painful slow games... are mostly blasting away at 3min blitz?!

I personally like 15/10 the best now . I used to love blitz earlier , but now I like thinking a bit more and get flagged a lot. So, if you ask me 15/10 is the most balanced time control, neither too long, nor too short

@Bong... am agreeing with you. I0 min be fast and fun but feels like real Chess. Fast blitz can help learn opening stuff, but will surely harm one's slow game by ingraining bad habits... not checking, moving on instinct, playing hope moves etc. Longer than l0 can get boring because it's only online, casual play. And many people are busy. What these master guys forget... the game should be Fun? If you have a rookie player sitting l0 or l5 min waiting for opponent move... they might get bored, not play again?
Daily is the best if your way is think deeply the chess, but in short matches I prefer Blitz 15 min.
15 min is not blitz

https://chessmood.com/blog/what-chess-time-control-to-choose very useful article on this topic.
I like the article links you have been leaving and this is a good one to show some of my friends. I knew about the time control differences, but this article words it nicely from the perspective of "purpose." Naturally, I knew this as well - but it is better phrased here than I would have come up with first time around.
Mine is 10m blitz but I'm seriously thinking to switching to 15/10
Everybody post their opinions.