I take the stairs all the time, habitually now. Even to the animal facility on the 7th floor, and I might go there several times a day. That's a lot of stairs, and sometimes I'll stop halfway up 4, and just stand there, stretch my calves, catch my breath. 4th floor is the pharmacology dept. One day I was standing there taking a break when the Pharm dept head came through.
"Are you all right?" he asked.
"I'm just taking a break on my way to the rats," I explained.
"There's this thing called an elevator just over there," he said, amused.
"I know, I just like the stairs."

I do like the stairs even if I have to take a breather at 4 1/2. Whatever I was thinking about before I got to the stairs, as soon as I reach the stairs I stop thinking about that and I start appreciating that my knees work so well. That my heart is pumping so strongly and my lungs are at it.

I take the stairs because I CAN.