Well, personally I think if you play $5/$10 you'll make mroe than you do in $2/$4.
In theory this is correct but in practice its not. I make a living from poker playing off a bankroll of $10000-$20000.
If I wanted to I could easily move up and play $5/$10 no limit but the fact is, its not as profitable as playing $2/$4 because the standard is hugely better at $5/$10.
You cant bully people at 5/10 like you can 2/4 because everybody defends. You also cant play tight aggressive at 5/10 because you will be bullied unless your willing to put all your cash in the middle regularly. In order to beat this level you need to mix your play up alot and hope the cards cooperate. You need to always bring your A game and sometimes you can see your entire stack dissapear fast without even being involved in a big pot. Its tough.
Limit on the other hand is different. If you keep it tight and play high stakes limit, you can make gradual cash - but its slow and probably wont pay the bills unless your at least playing 20/40, 30/60 or 50/100. Which you'd need a massive bankroll for.
It you want to make a living from poker your best bet is to first become a very good player at the higher levels, which isn't easy and make sure you develop your bankroll accordingly.
Having to pay bills from poker is tough though. If you dont win one month - realistically, you could be homeless. Its a stressful job and as a result in volatile games like No Limit you can go broke very easily.
To safely even practically consider going pro you need to become a very good limit cash player at high stakes and continously have winning sessions.
I cant rely solely on No Limit to bring home the bacon every month because its a volatile game, but I can always turn to Limit to grind out profits.
If you really are considering going pro now, I'd say - master games first and bring your bankroll up to a large amount and maybe consider switching to full time poker in a few years time maybe even 5 if you've seen a nice sustainable profit that you think could improve your quality of life if you had more time to play it.
To be a pro player you cant want the luxury lifestyle of playing poker for a living. You need to be certain that, by not working in a full time regular job - you can earn more money from poker than you would if you did work in a full time regular job.
Many people dont take going "pro" seriously but its no joke having a mortgage and bills to pay every month and no fixed income...
If short term you need to make a good profit at poker I would say, drop no limit poker and takeup limit seriously. Also in order to be a good limit player, you need to forget everything you learnt about how to play no limit, because hardly any of the fundamental basics to successful no limit play apply to limit.