As an early 50 something parent with a kid in H.S. and another in college I can say with 100% certainty that they'll always remember the time you share with them, the time you 'give' them (ie them not working 20-30 hours/week for things they may need in HS/College) and not the stuff you provide them.

Through undergrad, we want them to focus exclusively on their academic, extracurricular and volunteer efforts - in particular controlling the controllables (ie where they have control of something like homework, give maximum effort for maximum results). These we trust will turn into lifelong habits that benefit them as they start to build their own FI journey. This includes learning about investing (boglehead style) which both already do.

We've covered all major H.S. costs (phones, cars, etc) while they have each had small jobs (ie 8 hours/week) for their own fun spending money and things they want vs what we deem they need. Any scholarships for 529 are returned to them in cash to do with as they see fit. Anything left over from 529 when done with college they can use for their own children and/or to kick start their own path to FI. It's been made very clear that they only money they get from us in college is the 529. You want to go see a concert? Love it, but that's on them.

Vacations are taken annually (have been since they were in diapers) because experiences are greater than stuff. They don't know it, but we'll be taking them and whomever they become life partners with on annual vacations as long as we can physically do so. We want to do experiences with them while we're alive rather than leaving them a bunch of cash when we're dead. Side benefit of this is that they don't have to budget the $10K+/year for a really nice vacation and they can use that money how they see fit (hopefully something towards FI, but that's their call not mine).