The past 2 years I was working part-time for a startup as I am running a business of my own which is almost on autopilot and allows me time to work on other things as well.
After 2 years I realized the positive and negative sides of working for a startup that is hard to find out before working for one.
First of all there were 3 main guys running the show. Only one of them was a tech guy, the other two came from a business background with no tech knowledge wanting to build up a tech startup. Joining that startup as an early employee didn't mean much apart from getting close to 1% in options (which is nothing considering my contribution to the cause was worth way more but obviously 1% is an industry standard).
The work became increasingly more demanding, although they knew I had other things to do and I was part-time, I was asked to work more than what was normal and almost reached working full-time helping them out (which was stupid of me, I was sacrificing time that I could be doing other things).
The paycut I took also from my previous part-time gig was about 40% which is almost half.
The cause of the startup also started changing increasingly and although at the start I was keen to have the paycut etc it felt like I didn't belong anymore (thats important for others wanting to work at a startup to know. The idea is not gonna remain the same as it is especially with business people driving research all the time).
The only positive was that I got some more experience on as a fullstack than before as I had to work a bit more on aws and backend systems and also was using "newish" tech.
My honest opinion and advice to anyone that is willing to try out working for a startup is:
Don't compromise your salary and well-being.
Startups will offer you options which is usually crap unless you are a co-creator. If you are taking a paycut but you support and like the cause of that startup then ask for a bigger %.
Realise that most likely the startup is not gonna vest or sell and generally think of your options as a gamble.
Its most likely that the chances of you making real money out of your options is the same as you winning the lottery.
If you are asked to work hard and stupid hours, then reconsider your well-being and ask yourself if its worth it.
Also look at the composition of that startup. For me personally it was stupid thinking that 2 business guys having the biggest % in the company would ever work for a tech startup. They contributed in writing long essays and doing research all the time, but at the end they couldn't attract more engineers by paying shit salaries and giving out 0.2-1% in options. The product failed because it couldn't be delivered on time due to having less people working on it than it initially required, and because those business people in order to justify their own % to the company were going on heavy research and constantly deciding shift changes on the product completely out of the blue just because they had nothing else to work on. (we were supposed to release within the 1st year which would be a year ahead of our competition. We released after 2 years which gave competition the lead of releasing before us and a much better product)
All in all - don't sacrifice your salary, thats how you feed yourself and your family and someone elses weird-ass dream is not gonna make you silly money out of the blue. And also remember that working should be taking some part of your day, but you also have one life and working your ass off for someone elses shitty dream aint worth it.
Every person taking equity needs to justify their value now
This means that a setup with two "business people" founders need to justify their worth immediately. Not with promises of future sales. Not with vague research.
Worthy ways to prove their worth could be raising a giant amount of funding, or putting their own money into the startup as a sign of skin-in-the-game, or purchase orders standing ready to purchase the product once it is complete, or paid PoCs. Or serious track record of delivery/wins.
If you find a setup where engineers are taking all the initial risk while "business founders" stay on the sidelines waiting for a product to be built until they start to work -- run away. Think about it this way -- they have all the upside (they can choose later to work or to flee) while you have all the risk (you invested your pay-cut for vague promises of future work.)