Is cleaning computer fan improve performance?

When we send our computer or laptop to computer shop for maintenance, sometimes we will get recommendations to clean the fan with the reason of to improve the performances.  I received a call from a friend asking for my opinion on this, and I straight away answered it no. Moments later, I started to ask myself back whether I gave her the right answer because as far as I understand, cleaning the fan will only improve the heat, from overheating whatsoever.

Are you sure?

So I made a quick google and found out there a lot of discussions on this. To sum up, I can confirm that NO, it will not improve the performance.

However, cleaning the fan will keep the performance of the computer or laptop to where it supposed to be. Too much dust will cause heat build up, in which case your CPU may throttle down its performance resulting in a general lack of performance. 

What? Make up your mind

The right question should be as per below.

Is cleaning the fan improve the performance? No.

Should I clean it? Yes.

As simple as that.