Excellent reply, clean the sensor as often as it needs it. Not more. Not less.
In lieu of that. I was taught an easy way to find the few spots within a photograph and remove them. So, with me, it's clean when absolutely necessary.
JD750 wrote:
The answer is clean the sensor as often as it needs it. Not more. Not less.
Take reference shots, now and save them. Take them after every cleaning. They will come in handy.
When you handle the lens don't touch the glass and don't drop it. Change lenses in a clean area free of drafts and dust.