You know you're getting older when...

• you have forty and fifty year olds in your weekend peer group.
• your everyday speech includes sentences that begin with "Indeed."
• you suddenly need a week to recover from a all-nighter.
• "all-nighter" now refers to an evening when you stayed up until 3 a.m.
• you have a substantial collection of spare buttons from the professional clothing you've purchased.
• it's no longer "professional clothing" to you; it's just "what's in the closet."
• you routinely refer to your college students as "kids."
• you're struck by how kid-like those students appear.
• you favor dark over milk chocolate (although you still dip the former in peanut butter).
• you polish off an entire box of animal crackers... and neglect to study a single animal before they're gone.

I'm sure I'll spend the rest of my life adding to this list. I'll add items as I think of them — or as others remind me of them.