I know that South African Engineers keep a similar log book to pilots which is needed for License renewal. I think its a good idea especially if you move around a bit. I have been asked for experience sheets when I started at a new company. Its difficult trying to get retrospective experience together especially when you've left a company and no longer have access to their maintenance records. Keeping a real time log book might take a bit of discipline but would be worth it in the long run. Keeping a sample of work log book should be easy enough to do.
On a practical note, I knew an engineer who kept an exact record of every job he did. He was unfortunate to be dragged into an investigation into a serious incident. He was able to produce his log book showing exactly what he had done and was subsequently exhonorated by the C.A.A. on the basis of that information.
Regards
SomeFokker