Almost 1 year or maybe more that much I remember
9 months or so of playing (2012 - 2013).
Quit for some time and then emps was shut down (idk how long it was shut down for).
Came back after it was back and start "FRESH."
Begin playing again in November of 2014 till now.
So probably almost 1 year or so.
So you can say it takes me 1 year to be max (2179 total; all 99's) all thanks to DOUBLE EXP hahahahhahahahah
Without that, I doubt I'd get max in such short amount of time. Before I quit I had like 17 99's already so came back to work on the rest.
Begin my inactive already as well.
Some people took like 3+ years lol.