Long enough that the account has a history a moderator can scroll. In days, that is about a month before the first product mention, and about three months before the account is treated as established. Here is the lane we use and why each stage exists.
Stage one: new (days 0 to 7)
Helpful replies only. No links, no product names, no original posts. The point is to exist: to have comments in a few subreddits that a person could read and think "fine, a member."
Two or three replies a day is plenty. More looks like a bot.
Stage two: warming (days 7 to 30)
More replies, and the first original posts: a question you actually have, a write-up of something you learned. Still no mentions and no links to your own site.
This is the stage founders skip, and it is where the ban rate lives. An account with two weeks of real history survives its first mention; one with two days does not.
Stage three: established (days 30 to 90)
Mentions are allowed, with disclosure, in threads that are asking for a tool, in subreddits whose rules allow it, inside the 90/10 rule. Links only where the subreddit permits them. Caps are still tighter than a mature account's.
Stage four: trusted (day 90 on)
Full caps. The account keeps this status only while its ratio stays honest and its health stays good; a wave of removals or a shadowban resets it to the start of the lane.
Age counts from the real creation date
If you have a five-year-old personal account, it starts at stage three or four; you do not need to pretend it is new. What matters is real history, not the date you started marketing. The exception is an old account with no comments, which moderators treat as new.
Bought or aged accounts
Do not. A bought account has a history that is not yours, often a history of spam, and Reddit links accounts by device and behaviour. The ban takes your real account with it. Everything above is cheaper than that.
Making it automatic
Gorilla Desk computes the stage from the account's real age and health, and the publishing rules follow from it: what a draft may contain, how many go out, where links are allowed. You cannot skip a stage, which is the point.