Hello members,
yesterday i noticed, that my lens do not autofocus. I started to check my camera settings, but nothing changed.
When i turned off my Image Stabilizer, push shutter button half the way, i heard, that lens tries to autofocus - i hear high frequency sound, but nothing happen within lens.
Finally i detached lens from camera and looked to the contacts. They appeared perfectly clean, because this is my only lens and i do not detach from camera often. I tried to touch contacts with clean and soft napkin, then attached lens to camera and autofocus started to operate.

Now i think, is this a sign, that my lens need service?
Maybe i should send to canon service?
Or is this almost normal, when happens rare?
I have my lens 2,5 year and this is first malfunction.

P.S. Sorry for my not so clear english.