In most cases, you will be fine. Here's a couple of 'gotchas' to watch for though:
- Ask to inspect the disk before purchase - if the disk is scratched up, it's likely it won't work well. If you are unsure about whether the disk will work in the scratched up state it's in, don't buy it.
- A few stores that sell preowned games have a 'disk insurance' service (they all call it something different), that costs a couple of extra dollars but allows you to trade a scratched game for another copy within a couple of days. Totally not worth it, in my opinion, especially in Australia where consumer law has pretty strict refund policies for non-working items, but the option is there should you choose.
- Check whether the game has an 'online activation code/pass' - This was a common practice in the PS3/Xbox 360 era but has sort of died off a bit. Some games shipped brand-new came with a one-time activation code that allowed you to play online. If you bought the same game preowned, you wouldn't be able to use the activation code and thus would need to pay an additional 'fee' to activate online play.
- Do a search online before you purchase to check if the game requires an additional activation if you plan to play online.
Those are the only real concerns when purchasing pre-owned disk games - other than these the game should be no different from a brand-new copy.