If you tumble dry everything do you still need a hot wash?

Thanks Andy.

good point about max temp to wash - was always thinking the reason to wash at lower temperature used to be so colours would not 'run' - ie if the colours were not colourfast , if you washed something of colour that was supposed to be washed at 40c and you washed it at 60'c or higher then the colours could run and ruin the other washing , especially if you had something white in the drum some other piece of clothing .... and then eventually fade colours if you were washing coloured stuff at 60c or higher if on the label it said was at 40'c or under.

heres another thing - what 'shrinks' clothes is it when you wash stuff in too hot a wash or is it if you wash something in too cold water? - I always get mixed up with that one

Maybe the reason some items say 40 degrees only is still to do with colours running. But many just can't cope with the high temperatures. The hot temperatures cause items to shrink.