Taking care of knitwear

[Celery]

Please talk me through how you look after your knitwear.

It doesn't matter what I do, it doesn't matter if they're expensive or cheap. It doesn't matter what they are made out of. My cardigans always look old and tired after only a few washes.

Please talk to me as if I were an idiot, and tell me what to do.

Watching this for tips as I have a cardigan which needs to have its first wash and I'm putting it off as I know it will never be the same again.

The only instruction is to use mild detergent.

I use waitrose own brand wool wash, and the handwash prog on my washing machine, dry flat (on one of those fold out clothes horses you get from argos) and fold to store rather than hang