Wait If You Don't or Barely Meet the PC Requirements
If you're in possession of an old Windows PC it barely meets the minimum or recommended spec requirements, you should probably hold off until you can gather feedback about the game's performance.
If your computer doesn't meet Battlefield 5's minimum requirements, there's a good chance it won't run. If it does run, the game will likely be unplayable.
If your PC barely meets the minimum specifications, you'll likely be forced to turn the graphics way down which could hamper your experience.
If your Windows device is teetering on the edge, make sure you dig through feedback from other PC players before you buy a copy.
If you have concerns, wait until you're able to upgrade your Windows PC. Otherwise, you might have to return the game.
As a reminder, here are the minimum and recommended PC specs:
Battlefield 5 Minimum Requirements