You talk about things like property taxes and 401k contributions more often than you ever thought would be possible
You seriously weigh whether a drink is worth the bad sleep and headache it'll cause you
Your pop-culture references are lost on younger folks
You start referring to college-aged people as "kids"
You need reading glasses but you're in denial about it
Injuries take longer to heal
Those of your peers who haven't taken care of themselves are starting to have serious health issues
You care more about flossing, skincare, fiber, and hydration
You still rock bottom eyeliner like you did in high school
You've seen fashion from your high school years go out of style and then come back as "retro"
You see the utter confusion on your nephew's face when you explain that you used to keep a quarter in your bike pouch in case you needed to call someone, because he doesn't remember a time before cell phones and his generation isn't allowed to just roam around unsupervised on their bikes
You have strong opinions about things like laundry detergent brands
Birds become fascinating
You have no problem spending a few hundred dollars on a new kayak paddle, but the price of cold cuts these days is just unacceptable
Eyes, motivation, you can't drink all night and only sleep for three hours, and in general it's better to drink at home, it's better to lie on the couch, lack of interest in many things.... taking care of children's health is above your own etc.