In general I think most people should have a goal of at least maxing out their tax advantaged accounts each year. Obviously that isn’t possible for a lot of people, especially early in their careers.
Investing just the match won’t make for much of a retirement unless the retiree has a lot of money coming in from another source.
For what it’s worth, I invest the TSP max ($17,500), create a back-door Roth IRA ($5500), and put many thousands of dollars into my ordinary brokerage account each year. I can do that through a combination of having a relatively high paying job for a federal employee and, more importantly, making those investments my priority.
I do the same thing as Paul, which amounts to roughly 20-25% of my gross income. More importantly however, is I’ve identified my retirement goals. This can be done fairly easily by projecting when you’d like to retire, what your spending in retirement will be, and how long you think you’ll live. After that, you can come up with a reasonable plan to hit that target.