Level of Details polycount?

When using level of details we will use Low poly, Mid poly and High Poly
so how many poly do you recommend for each asset’s low poly, mid, and high poly
we will use it in a Open World Game with 4 towns with lots of house and shops and 1 ruins.

There’s no correct answer to this. Crunch your models and do some tests, then choose the results that you and your team are happy about.