Having a degree is a binary thing. You either have one or you don't and there is no middle ground. You can have all the knowledge equivalent to having a degree, heck you could be better educated than most graduates, but it doesn't mean a thing when your resume' is trashed due to no degree. And that is really the way it is, degree or no degree - binary.
Does it have to be a STEM degree for an engineering position or will anything pass the HR droids?
I feel some assumptions have being made about the original poster, one is that they want to go into further education for the money. If this is true, then I doubt doing an engineering degree will get the best return on their investment. I don't know about the US, but in the UK an engineering degree certainly isn't the best thing to do, purely for financial return: economics and law are probably better options.
If it's not about the money, then it might make more sense to study something completely different, get a comfortably paid job and informally study electronics for a hobby.
Hint: It doesn't get easier as you get older. Get started!
That's true. I have thought about topping up my HND to a degree, which I could theoretically do by studying for another two years full time (I've done a quick Google and the HND is higher than the US associate degree). In reality, I'd have to do it part time, which would involve a lot of, late nights and travelling in jammed traffic. I currently earn enough to overpay my mortgage, so there's no financial motivation there.
These folks are making some pretty nice money!
Not really. $150K is decent living, but not more. Half or third of your after tax money will go towards rent, and with a salary like that you can forget to ever buy a house.
?
When I left corporate America my salary was less than that and I bought a house, paid it off over 15 years and I have no loans for a cars, credit card debt etc.
About 60% of people in the US own their own home but only about 5% earn $150K or more. The median salary in the US is less than a third of that value.
If you still have to rent on that kind of salary then you're being reckless with your money.
Why? In some places renting makes more financial sense. It depends on whether on average, house prices annually rise much faster, in terms of the percentage, than the interest rate or not and how often one needs to move.
If house prices in your location are static, but interest on savings is good, then it makes more sense to rent and save the rest for retirement. If you need to move fairly frequently, then again, renting is the more sensible option.
Of course in the UK house prices have risen above interest for a long time, so buying is always better, than renting, unless you move more often than two years.