How hard is it to bleach your own roots?

I’ve been coloring my blond hair for years at the salon but it always turns back yellow in about 1 week. Gone to the most expensive salons and it just doesn’t last and it turns yellow in one sec. I’ve tried all the products to get rid of the yellow but nothing happens.

So I’ve decided it’s time to bleach my hair. My hair grows fast and I know it’s gonna need a lot of maintaining and I can’t afford to go to a saloon to re bleach my roots all the time so how hard is it to do at home?