Under car clean and treatment?

Hi,

I have a 2006 avensis, which is old and has been maintained like an average consumer.

I was thinking to clean the under of my car, including the components to determine where there is rust, and treat it.

Has anyone undergone such a procedure? If so, how long did it take?
Do you recommend any tools or any tips in general.

I don't know if I can be asked at the moment though. or may considering paying someone to do it. does anyone know how much a company would charge?
I would like to prevent any major rust issues, rather than having to purchase another vehicle due to rust.
Thank you