I generally recommend the [Bogleheads](https://www.bogleheads.org/wiki/Main_Page) theory of investing. This involves investing in a few ETFs or mutual funds as a diversified portfolio. For example, a [3 fund portfolio](https://www.bogleheads.org/wiki/Three-fund_portfolio). I use [Schwab funds](https://www.bogleheads.org/wiki/Charles_Schwab), but any with low expense ratios will suffice. This is a set and forget strategy that requires very little work.

An important piece is figuring out your [asset allocation](https://www.bogleheads.org/wiki/Asset_allocation) for each fund. The simplest setup is just use a [target date fund](https://www.bogleheads.org/wiki/Target_date_funds), picking your expected retirement year. [SWYGX](https://www.schwabassetmanagement.com/resource/swygx-fact-sheet) is one such Schwab fund with a target retirement date of 2040.

TDFs follow a [glide path](https://www.bogleheads.org/wiki/Glide_paths) that generally invests in stocks when you are young (higher risk), and moves towards bonds as you get older (less risk). You can push the target year later than your normal retirement year if you are comfortable with more risk for a longer time.

Target date funds are not a good idea for a taxable brokerage account. They are mainly only good for a 401k or IRA account for tax reasons. See [this thread](https://www.bogleheads.org/forum/viewtopic.php?t=408592) and [this SEC filing](https://www.sec.gov/newsroom/press-releases/2025-21) for why.

This brings up an important question: are there TDF-like funds that can be used in a taxable account? Yes, [iShares](https://www.ishares.com/us/strategies/what-is-a-target-date-fund) has some. [This reddit thread](https://www.reddit.com/r/Bogleheads/comments/1jc8h03/why_vanguard_does_not_offer_a_single_etf_that/) has some good pointers.