Playing on WoW Private Servers: Does It Affect Your Retail Account? No

No impact. Private servers are unofficial, run by third parties. They use:

• Separate databases, accounts, characters.
• Different client patches (often older expansions).

Your retail Battle.net account, characters, progress, and subscription remain untouched.

Caveats

• No Blizzard Support: Bugs, hacks, wipes = your problem.
• Legal Gray Area: Blizzard tolerates but doesn't endorse; DMCA takedowns happen.
• Security: Never use your real Battle.net email/password on private servers.

Play both freely—just don't mix credentials.