I don't know how much you make or where you're living. It could be you're one of the many on HN that is making over $300k/yr with just a few years of experience. That said, I'm 27. About 5 years in now as well. I live in the bay area and work at a startup. I'm definitely underpaid by a sizable amount. Anyone at google or fb is making more than me.

I think the first things I used to buy were furnishings, cooking equipment, computer upgrades, a tv, a bicycle, a newer car, a motorcycle, tools, a fitted suit, and so on... Just whatever interested me. Spending $2-3,000/month on "non-essentials" feels like it happens every other month. It's a lot but it happens because I have a lot of interests. I ride the bicycle to work and so that made sense to buy. (I also sometimes enjoy bicycling) I watch movies and shows on the TV. I play demanding PC games. I like to cook all kinds of stuff. I like having a mattress that isn't 25 years old and doesn't hurt my back. My last car was totaled and I'd been borrowing cars for a year. So I decided to buy a BMW 135is because I wanted one for so long and I like sporty convertible cars. I bought a motorcycle because I've wanted one for a decade. I bought tools because I work on everything by myself. I bought suits because it's one of the few things I look good in.

I spend the money on what I like to do. Money is definitely my most limited resource these days because I happen to like a lot of things and those things be expensive. I like my car but I'd sure love to have a GT3RS. I like my motorcycle but a S1000RR or R1M would sure be more exciting. I can take decent photos with my camera but the tech is a 8 years old and the noise in low light is terrible. I'd love a new L lens or a A7Riii to take some better low light photos or better portraits or nice strobes to get better lighting.

What I'm saying is that my demands seem to be a lot larger than yours, I guess. Be glad yours isn't and keep it that way. Save as much as you can for as long as you can. It's definitely better to be satiated than starving. I also don't live a "FIRE" lifestyle because that's not my goal. I want to live a bit while I'm young. I want to be able to drive fast and ride motorcycles and do all the things before I feel like I don't have the option to anymore. (And depending on your future spouse and future standard of living, this could be a real issue!)

I still max out my 401k and IRA every year. I still save more on top of that because it's not enough to meet retirement goals. I try to save 20-25% of my pre-tax income every year. 401k+IRA isn't enough to meet that so I have to save a decent amount of post-tax money. I typically invest in vanguard index funds. Pretty straight forward. You can use their target retirement funds to just get started.

If I was making over $500k/yr, I think that's when I'd start to feel like I made a lot of money. But, where I live, even that doesn't feel like a lot because that's the level of income that's just barely enough to buy a updated house where I live.

A long time ago, $100k/yr sounded like a lot. I grew up in a very rural area with very low incomes. But, now, it sounds like pennies because houses where I am are regularly $2,000,000+ and they're like 1500sqft on a 4500sqft lot with 1930-50's construction.