Lots of good info on the thread and remember that everyone reading this is not in the same boat money wise.
Some here own businesses,get paid as a 1099 r, work for a company and get W-2's and have access 401k, 403B, etc. Some have 1 person incomes, some have 2 person incomes.Some have kids or other family to care for and some of us have more debt than others.

Twenty years ago my account slapped me up side the head and told me to open a brokerage account, a self directed 401 K, and a Roth IRA with Schwab. I had just finished raising two kids thru college as a single parent and was self employed. I started funding my 401 K to reduce taxes and put any that was left into my Roth. I also bought a couple stocks in the brokerage account.

As I said in an earlier post that Schwab interface is the easiest one to use even though I have a Fidelity account that gets my SS every month and has some dividend paying stocks in it.
I've also had a Dean Witter account ,an Ameritrade, and E trade accounts. I also have a 401K thru my work .
You can have more than one and some one stated that Schwab has a sign up bonus and maybe other do also.

ETFs are so much easier to buy and sell than Mutual funds. That's why they are growing so fast and you can pick exactly what type you want, Buy today and sell tomorrow especially if the dems look like they are going to get in next year.

Remember that funding your 401 K, 403B, reduces your taxable income. I'd much rather put money in a retirement account than give it to the government.

If you are a business owner or self employed you can fund over 50K a year. You can also do a Roth IRA which is funded by after tax dollars. Doesn't reduce your taxes but grows and you don't pay any tax when you take the funds out.

Different strokes for different folks but I hope this helps.