I'm moving .... to a bigger room

I'm moving to the master bedroom now ..... much much bigger space to store my ever growing possessions..... i got the tendency to keep things even though i do not need them....HOW TO GET RID OF OLD STUFF? I'm very sentimental, like to keep my stuff even though i do not need them anymore, that's why my assets ever growing..... Sigh! have to continue to unpacked things..... can't imagine if i moved house next time......