At what point do you stop milking free marketing and actually spend the budget?

Context: early stage consumer platform, small team. All marketing so far has been free. Organic posts, Reddit, community building, founder content, warm intros. It's working, slowly. Signups come in, we can trace most of them to specific posts, and the cost is nothing except my hours. Which is the problem. My hours are the budget, and they're maxed.

We have money set aside for marketing. We haven't touched it. Every time I think about spending it I talk myself out of it with the same logic: paid feels like paying to skip the work of learning what converts, and if the organic stuff still has room to grow, spending money on reach feels premature.

But I also know "we'll spend when organic maxes out" is one of those rules that sounds disciplined and might just be fear. There's always one more channel, one more post format, one more community. You can hide in free marketing forever.

So, for people who've actually made the switch, three questions:

1. What was the signal that told you organic was done being the main engine? Was it a number, a feeling, a wall you hit? I keep looking for the line and I can't find it.
2. When you did start spending, what did the first dollars go to? Boosting what already worked organically, or buying reach in channels you couldn't touch for free? Everyone says "amplify winners" but I'd rather hear what you actually did and whether it worked.
3. Anyone regret spending too early? The horror stories are always about burning money before product market fit. But I never hear from founders who spent too late and let a competitor buy the audience first. If that was you, what did waiting cost?

The honest version of my situation: organic is producing, but it's producing linearly, and every unit of growth costs a unit of my time. Paid is sitting there as the obvious way to break that link and I keep not pulling the trigger.

Tell me if I'm being disciplined or just cheap.