Safe withdrawal rate of 3% for 25k/ year (countries out side US are closer to 3% than 4%) means a stash of 820k.
You are there if you don't have to buy a house out of the $750K
If you buy a house @350k and have 550k left, you've got about 22 years of expenses @25k.....you could do it if you spent less, and felt safe with a slightly higher withdrawl rate of 4% ie 20k at 4% = 500k.
IMO you certainly have FU money....but as for never working again ever, that might be a little tight depending on your tolerance of risk and satisfaction with living permanently on 20k.
If you were planning to quit because your job really sucks, and find something else , a part time gig, or seasonal work or intermittent contracts, lower paying but more satisfying work etc, then I think you have enough FU money. With that size stash you only need to cover your expenses (25k) with work each year... and the stash should keep growing. You don't say what your current income is, but I'm betting its higher than that to get the size stash you have at 30. Could you negotiate to work part-time to cover expenses? Working part-time makes a sucky job a lot more palatable.
Congratulations on your stash! - you've done well, and will soon be able to reap the rewards of this great foundation.