How many buy-ins is needed for safely playing low/micro stakes MTTs? I'll be playing on the Ontario site so fields are smaller. What type of ROI could someone expect with a decent understanding of poker?

Question is lacking key details, namely:

1. Are you planning on capitalizing your poker endeavor only once, or are you prepared to allocate additional funds if things do not work out initially?
2. What is your time horizon? How much volume do you think you'll put in over that timeframe?
3. What do you think is a very conservative estimate of your true ROI?
4. What is your risk tolerance? In other words, how often are you willing to stomach losing your entire roll over your time horizon?

A sensible answer depends on all these. But whatever the answer is, I will wager that it's a lot higher than you might think.

If you're playing smallish fields (200 players) are breakeven (0% true ROI) then 350 buy-ins corresponds to a 99.7% security level over 500 events--0.3% of the time over that sample you'll lose at least that much.

Sorry for the super late response.

1. I can reload as I can afford if I bust my roll. I'd be starting at the bottom and working my way up so reloading isn't a big deal.
2. Not sure what you mean, I'd just be grinding what there is available on the site (ACR now) so maybe like 15-20 tournaments a day?
3. I have no idea. Can probably beat 10NL maybe 25NL and 50NL.
4. I don't mind busting my roll at the micro stakes as long as I think I'm a winning player.

Just wondering what type of ROI a decent player could expect at micro stakes MTTs. Or what type of ROIs could different players expect? Like a decent player, a good player, a very good player, the best. What about for low/mid/high stakes?

Your question on bankroll only makes sense if you are assuming that you are a winning player. If you are a losing player, then no amount of bankroll is safe - you will go bankrupt if you play enough MTTs. Your bankroll needed as a winning player is another question, and there is no one magic answer. MTTs have high variance, so you can certainly expect to lose a lot of them even if you are a winner. I have heard 50-100 buyins floated around as a guideline, but I’m not sure what ROI and what risk of ruin are assumed to get that number. Since you are willing and able to reload if needed, though, and that your risk tolerance is fairly high, that would seem like a reasonable starting point.