I used to color my own hair at home with Nice n Easy. I would use the lightest blonde in order to achieve the lightest blonde possible on my golden blonde hair.
After years of doing that my hair had a series of color lines where I accidentally overlapped touch up colors.
I had to have a color correction expert take it darker to neutralize all the lines so that my hair look more natural and dimensional.
I personally believe trying to fix your hair color problems yourself is a mistake. That's just my own opinion after having my own issues and knowing that when I tried to fix my hair color issues, I only made them much worse.
In my humble opinion everyone needs to do what works best for them, their budget and their circumstances.