Don't throw your clothes away just because they don't fit or they've gone out of fashion!
See also: How to care for your clothes so that they last longer
See also: How to remove armpit stains from your clothes
Take them along to your nearest tailor and they can change them as if by magic. For example, they can:
Change the sleeves
There are many options for altering sleeves that are too big or too small. If the armhole is too tight, the tailor can drop it to make more room. The extra fabric can be used to loosen the arms or remove the sleeves to change it into a tank top.
Create a different neckline
The tailor can remove the collar and turn a top into a crewneck or boatneck, for example.
Custom fit your jeans
A tailor can adjust every single aspect of your jeans until they look like they were made just for you. The only requirement is that the denim should fit you well through the widest part of your hips.
Your tailor make a dress bigger or smaller so that you can get into it, and remove pleats from trousers or skirts.