Can I implement testing and informal assessment in my teaching context?

I think that the most difficult part of being a teacher is when the moment of giving grades comes. I really hate that part because nowadays the most of the students wants to get the highest grade for nothing and it doesn´t fit in my mind, But also there are some students that always show their interest and commitment with the subject, but for them it's very difficul to get high grades if we as teachers only use the traditional ways of assessment. For that reason, I always combine both ways and I help those students who really deserve it.