Apparently our experiences may be different, but I clean the sensor about 1-2 times a year. I mean exactly the wet cleaning.
Is it risky? Maybe, it depends. If You have right tools and don't press to hard on surface of the sensor, then...
Right tools? Yes! If You are cleaning APS-C sensor, then You must use APS-C cleaning swabs (not swabs for FF). Secondly, there must be special cleaning liquid (not enough just to isopropyl alcohol).
If You follow these advices here in the clip accurately, then You don't take any risks.