do you last longer with certain MM?

So I was on the hunt today (review will be posted once AH site is update with pics and such) and surprisingly I lasted a lot shorter than the last 2 times I was with an MM. The longest I drilled MM was 5-10 minutes and thats a long time for me. Lol I wanted to test myself so I went back to that same MM and again I lasted 5-10 minutes. Confidence went up but then today it went downhill. lol So yeah have any of you had this kind of situation?