How to make your clothes last longer?

I'm one of those guys who has a very tiny wardrobe and only has few pieces, I buy quality stuff ( obviously for good prices) and wear that piece till it's done - and than can be used to do some messy household works till its totally done.

However... how do you get the clothes to last you as long as possible? Seems like the first time I get them they last weeks before They get dirty and need to be washed, once they are washed- boom, the life-cycle between washes starts to decrease every time you wash them and soon the piece gets dirty & shows wear within only few days... What's this wizardry? I line-dry them and wash them on gentle/short programs but still...

can anyone aware me on what's the correct way?