I think it's wrong to say it takes 1 year. If you look at the top players progression, I think it takes at worst 6 active months to get a solid top 15 level if you organize yourself, are ambitious, highly motivated and possess a strong mental.
To illustrate the timeframe, let's take Magav as the lambda example. He was not particularly giften when he started playing TE and competitions in summer 2013... But he managed to reach US Open final of 2014, 1 year after his start.
July 2013 ---> Defeats vs
R32 ronyers2013 (El Salvador) 3-6, 4-6
QF sprock-93 (Italy) 37 6-3, 3-6, 6-7
R16 Felipe.M (Colombia) 13 2-6, 2-6
leonmonstroso (USA) 77 1-6, 3-6
QF sprock-93 (Italy) 38 6-1, 6-7, 6-7
In August W sprock-93 (Italy) 38 6-1, 7-6
OctoberR16 leonmonstroso (USA) 53 5-7, 7-5, 3-6
You see his summer slow progression. 2 defeats vs Sprock in July, finally a victory in August.
His matchs vs Leonmonstroso are more significant to illustrate his progression to top 20 level.
In July, he lost in 2 easy sets vs him (ranked only 77 back then) ;
In October he lost in 3 close sets.
In the very next tournament, he finally beat leonmonstroso, ranked 52, 6-3, 6-1.
At the end of O0ctober, he beat again leonmonstroso 6-4, 6-2 and tdbchess, ranked 13, 4-6, 7-5, 6-3
Magav finally won the ITST Open 2013 at the end of the season, which is the tournament for the guys not qualified for World Tour Finals.
So in 6 months, he managed to be the best of the guys outside the top 10. He finished the year at the rank 28.
How did progress like that ? No secret :
1) he played every challengers / future possible
2) meanhile, he played a
crazy number of practices sets
3) he frequently asked top players for matches, tips and feedbacks (at least he did with me).
3) he watched demos/videos of top players.
In 2014, he continued his progression and was able to compete with top players, winning several matchs in M1000 or grand slam vs Richie, Vramvrim & Vmoe.
The peak of 2014 was the US Open though : in Semi-final, led 2 sets 0 against Vramvrim, he saved multiple match points and won... Big mental ! He also reached the final of the World tour finals. So in less than a 1 year, he managed to get the top 5 level.
This season he was certainly the best competitor to Richie during the first part of the season, reaching the n°2 spot and beating very often Vramvrim. Since september 2014, Magav vs Vramvrim, it's 8-1 in Head to head.
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Other cases : Butcher, Richie, Vramvrim, IsniperXZ, Wilito, Pidzi, Clog.
- Butcher was like Magav was : playing a massive number of practice sets in a very short time, always asking the top players for "tips & secrets", ultra motivated. These guys have one common point : they didn't care to loose practices 6-0 against the top. They certainly loved the game and wanted to become top players. Butcher started in december 2013, he won Monte Carlo in April 2014 and Wimbledon in July, so once again 5-6 months.
- Richie & Vramvrim built their levels by playing together I think. A great partnership when you see their results. 4-6 months for them too.
- Two singular examples of spectacular progression could be Wilito & IsniperXZ.
Wilito last season, lost 6-0 6-0 against most top 10-20 players. This season, he was the unique player at RG to take a set from Richie. How did he do that ? Same as Magav : playing a lot and asking for tips.
IsniperXZ case is very different : he came on the tour in 2013, didn't have the level like every beginners, lost a lot in first rounds with scores like 6-1 6-1.
He vanished from tour as an anonymous, nobody knew his nick I think. ust before the AO 2014 started, everyone talked about one guy : IsniperXZ. He came from nowhere, destroying a lot of people in practice set on the lobby, playing at a great level whereas nobody knew him. Some people thought it was a fake or something

IsniperXZ reached semi-final of RG 2014 after beating Vramvrim and won several titles.
What did he do to explode like that ? He did what Pidzi & Clog did : practice a lot with AI until they finally get the level required to compete online. Pidzi is certainly the second best player all-time and Clog reached the final of Australian Open for one of his first tournament participation.
So it's not a matter of time, it's a matter of investment : you have 2 ways to become great, online or offline. But either way,
you must play a big quantity of play as everyone is telling you in the previous posts. If you play 1000 sets in 1 month, you will have top 10 level more or less
