During a flashback, a character who is clean shaven in the present will inevitably have facial hair during flashback.
- Everybody Loves Raymond. During the flashback to when Ray and Debra first moved in, Robert had a mustache.
- Home Improvement. During a flashback, Tim had facial hair, and Al was clean shaven.
- The Venture Bros.. While going through Hank and Dean's deaths, there was one part where Rusty and Brock both had mustaches. This is lampshaded where they remember how ridiculous they looked with them.