If you shoot indoors, you’ll likely want an f/2.8. It’s the difference between 1600 and 3200 iso or 1/250 and 1/500 shutter speed. I’d never shoot anything indoors (unless it was professionally lit) without f/2.8 lenses.
If you’re inexperienced with shooting sports, I’d suggest renting a lens and trying it out. Some people who try to shoot sports/concert photography for the first time get very bad results because their settings aren’t right. Use the rental experience as a learning process on what equipment you should buy.
If you shoot indoors, you’ll likely want an f/2.8. It’s the difference between 1600 and 3200 iso or 1/250 and 1/500 shutter speed. I’d never shoot anything indoors (unless it was professionally lit) without f/2.8 lenses.
If you’re inexperienced with shooting sports, I’d suggest renting a lens and trying it out. Some people who try to shoot sports/concert photography for the first time get very bad results because their settings aren’t right. Use the rental experience as a learning process on what equipment you should buy.