In 2E, you couldn't use a Hero Point more than once in a round for the same purpose.
Unless otherwise noted, spending a hero point is a reaction, taking no time. You can spend as many hero points as you have, but only one hero point on any given benefit per round. You can spend hero points for any of the following things.
So you could use a Hero Point to buy off Fatigue and one to Improve Roll, but you couldn't use a Hero Point to Improve Roll on your attack roll and then use it to Improve Roll on the Toughness save when you find out that The Trap has that name because his outfit manifests beartraps when struck.
I had thought that 3E had the same thing, but that line is missing.
Unless otherwise noted, spending a hero point is a reaction, taking no time, and you can spend as many hero points as you have. You can spend hero points for any of the following:
Can I get a confirmation that that sentence does not show up somewhere else in the core book, errata, or the Deluxe Anniversary edition?