Whats better for weight training?

alright atm im training everyone second day doing 1 exercise per muscle example: like preacher curls for biceps then like next exercise would be tricep pushdowns. like i do 3 sets of 8 for everything but this is just an example. what im trying to find out is if it would be better to workout like almost every day but 1 day would be chest next would be arms and all that and like on arms day would be preacher curls, then concentration curls then cable curls. like that so which one would be better. thankyou for all your help