Masturbation?

a lot of masturbation in life time is okay? sometimes I feel that semen is dilute and is not dense as was in my past. also quantity discharged of my is lesser than in past days. what is the reason? how can I once again gain that strength, semen thickness, good volume and healthy . I never used pills or such stuff for ual enhancement. I am 26 years old. so please suggest me the best solution of this problem. thanks