In an interview recently, I was asked the obvious question: “How many concerts have you played?” And I answered truthfully: “I don’t know.” I’ve thought about it before, even wishing I had kept track better. I might calculate the number by studying my old calendars and printed programs. (Could I have notched the leg of a piano bench?) It’s got to be hundreds.
As I was speculating about this, I asked another question: “For the purpose of this count, what is a ‘concert’?” Of course, evening-length performances with an audience in a theater. What about playing in somebody’s living room? What about the performance of a 
single short piece? Television? Open rehearsals? No wonder I haven’t kept track.
There are artists who monitor and record bodily functions, or document the mundane or arcane physical details of life. Ok, I’m keeping a log now. I’ll list each time I play the piano, for how long, and for whom…
For me, a concert isn’t one piece. However, I do think that monitoring your practice time is a good habit to get into. Good luck.