Why is my male cat peeing all over my house?

I have a year old male cat which i have had since he was 7 weeks old.. since i have had him he has always peed on clothes on the floor, rucksacks, carrier bags up the walls everywhere he can.. i thought it may have just been a faze from when he was younger but he has never grown out of it.. his litter is changed every 2 days and spot cleaned daily.. we aslo have his sister who is the same age and has never peed anywhere in the house.. i cant understand why he is still doing it as a year old male cat.. i dont want to get rid of him but i dont think i have many more options as my house is really starting to smell.... any advice would be a appriciated.. many thanks.