We install a plugin to speed up and monitor clients websites. Look at the load time in the before and after we went to work on a new client’s site today:
Needless to say, we have one happy client and we have only just got started.
EDIT: Added. We just got this result from another new client. Unfortunately we did speed up the site a massive amount, but are probably going to recommending that they change hosts. It is still too slow.