When do I start seeing results after hair loss treatment?

I am considering starting hair loss treatment, and I am wondering when the effects will start to appear.
I have heard that the time it takes to feel the effects differs for topical and oral medications.
I'm worried because I've heard that the dropout might increase in the beginning.
I would like to know how many months it usually takes to notice a change.
I am also wondering if the effect disappears if I give up in the middle of treatment.
I would appreciate reviews from those who have actually experienced this.