I just flagged something as opinion based and used one of my flags. This is my first time using flags, so I'm wondering if I use all ten (not that I plan to go on a flagging rampage) will I be put on a cool down or not allowed to flag anymore?
- default 10 per day
- one bonus flag per 2000 reputation
- one bonus flag for every 10 net helpful flags (helpful - declined)
- maximum 100
Once you've used up your flags for the day, you won't be able to flag again until the next (UTC) day. That's not a punishment; it's just to ensure that the flag queue doesn't get completely flooded in a short period of time. Note that if enough of your flags are marked helpful, you may get new flags in a given day even if you ran out earlier, by the third bullet point!
It is possible to get blocked from flagging for more than a day, but that's never permanent (it lasts a week at most, unless you raise even more bad flags) and only happens if you have too many declined flags. From this canonical main meta post (which also contains screenshots):
Flaggers with a recent (past 7 days) flagging history consisting of at least 10 handled flags where >= 10% of flags were declined will see [a warning] when they flag.
Those who've had 25% or more of their flags declined will [...] be unable to flag any further posts for any reason.
This does feel more like a punishment, but if it does happen, think of it as more like a notification that you're not flagging as carefully as you could be. The advice to review your own flagging history is genuine, and meta is always there for you if you need advice. And it's unlikely to happen anyway if you flag sensibly - flags raised in good faith are usually marked helpful.