Although I agree with and share your method, their mother and I differ in that regard. I was raised with nothing, my wife was raised wanting for nothing. We meet in the middle for most things and I always said that my kids will have it better than I did. But when you factor things in such as: if they paid for their phone they wouldn't have one; therefore mama couldn't talk to them. If they paid for their car insurance they couldn't eat (okay, exaggerating just a bit here) etc, etc. Suffice it to say that we don't have near as many apron strings as we used to but a few are still attached.
I had to learn to refrain from advice when I realized they were grown. Now I give it if asked, otherwise I just smile and say "oh...good for you" etc.
we older folk also have a tendency to see the problems and dangers in a lot of things because of life experiences and for a while I found myself to be "downer Dave" in that whatever the subject I would "warn" about possible problems. Realized, I wouldn't have listened much to that stuff either when I was younger.
I, like you, arrive early to appointments, if problems I manage to get there on time no matter what usually.
Our daughter when visiting never fails to forget something at our house, it's a running joke. I have long since given up on asking "you all have your telephones? Chargers? Shoes ? (Yeah, the grandkids forget shoes even!) jackets, etc.?" No matter what I checked they forgot something else. And always late, but then again, other than things like job appointments, etc, it seems to work out and not be a crisis.
Letting go of giving advice (when not asked for it) has been a total relief, and I'm a lot more fun when I'm not cautioning. The "kids" are adults, and they will make their own mistakes as I did and still do.
As for giving the kids what you didn't have...I have often thought of that. Just a hypothetical, but take a person that grew up poor, managed to work hard, and smart, and built up say a business, even got rich. Even though I understand the desire to "give them all I didn't have" why that person would deprive their kids of meeting challenges, being responsible, not having everything given to them, seems cruel to me. I worked in a lumber yard for a year to afford my first good guitar and amp. I bought a used Gibson ES-335 and an Ampeg Vt-22 amp...and I could not have been more satisfied or happy with it. Later in when I had money I'd buy other equipment, and not prize anything like I did that guitar and amp.
Many successful people (and musical groups) that make it, say that the most exciting and fun was getting there, the struggle and the rewards. Seems weird that a person would then just give the children everything, so they don't prize anything and never get that wonderful feeling of accomplishment.
And I'm not saying you do that, at all. I just mean in general.