Recently, I hit the milestone of 40, and I thought I would share some reflections with SN.
First off, I have never been a fan of big celebrations or things like that. I don't like attention, and never have. So even in school or when I was an office worker, I would never announce my birthdays. Since I don't have a traditional job and work at home, for celebrations, I just bought a box of Quality Street (strangely, you can find these traditional British sweets in Bulgaria) so everyone could enjoy them. Not needing much attention/validation is pretty great, actually.
Nothing feels different, of course, in my head I'm still like 25, and everything that came out in the early 2000s kind of feels like it was 5 years ago.

This year, I found myself just being very happy that I have a family that loves me and I have the health to do what I want, whether it's going on the trampoline with the kids, or just lifting weights every day. Money and income are still not amazing, but also not so bad that I can't stack some sats, and I don't hate my job and life.
I generally reflect on things a lot and quite often practise gratitude, but it hit a little different on the 'official day'.
Heath is important - people you know start dying around this time
I started thinking more about health optimisation in my early 30s, and I feel pretty good about this decision.
People talk about health being wealth, but few truly understand how important it is. It's very easy to get caught up in life with status games and forget the important things in life, which are family and health. Simple, but true. If a person can truly appreciate this, it gives a very powerful feeling of inner peace.
Just this year, a guy from my old friend group died of bowel cancer, leaving behind a wife and three young kids. Not a slob, just a normal guy.
Another classmate had a massive stroke and is not paralyzed and in a wheelchair, and a third just also got a bowel cancer diagnosis (wtf is going on with all this bowel cancer in young people!).
Things start to feel like a game of musical chairs where people are dropping around you. Presumably, as you get older, this tendency continues like some relentless, slow-motion squid games.
While a little terrified of cancer, I like to try and focus on what I can do. So, apart from my usual supplement regimen #846182 and checking my own blood tests, I will now add in PSA checks and maybe bi-yearly stool samples. Might do yearly ultrasound organ imaging too. Fortunately, in Bulgaria, this is cheap, and I can just get on with it.
My only regret and advice
I think my only regret really it's not stacking harder for the future a decade ago! I kick myself for my shitcoining and sins of the past when I was making more money, but I try to look forward. Regrets are a part of life, after all.
To any younger stackers that have the attention span to have made it this far (good job, by the way), I would say this: The most valuable things in life compound over a long period of time - wealth(sats), knowledge, confidence, relationships.
If you're here on SN, you're already ahead of the curve, so in line with btc philosophy, keep training the delayed gratification muscle, stack the best you can, read as much as possible, and avoid toxic people.
The old adage of chop wood and carry water is as good as ever.
For any other stackers out that have some sage advice and wisdom pearls, let's hear them