Some persons don't reuse addresses though they might not delete it from the wallet, so if they somehow get any BTC into the old address they can still get it. If the wallet is too old, then it may contain too much addresses. OR if you do something related to company and all, you may have these much addresses. Anyway, that's not the point here.

I didn't hard any limits, yet. I think there is no limit. But if you generate too much addresses in your wallet, it may become slow unless your GHz increases.

  ~~MZ~~