Around 2.5 years full time.
(my version of mastery is different from others, I just wanted a steady way to invest money for a 20-30% yearly return with low drawdowns.)
Theres quite many things to "experience" before you know what works and what doesn't.
I started with hundreds of ideas
I wrote 150-175 pages of code in tradestation to backtest many things. At the end, All I look is a bare chart with
volume, candlesticks and use radarscreen to scan for entries.
funny, how simple mastery becomes, yet so hard.
Order of competence.
1) retard
2) trader
3) edge trader
4) arb trader
5) simple (yahoo charts trader)