with my new computer I have a wu of Climate running for approximetly 300 hours, and this wu abort with a calculus error, at 64%...Is this very helpfull to give so more times to this project if the wus does not complete their work ?

Even not finished WUs send back intermediate results with trickles and some more stuff after every phase.
As the WUs start with some more or less random seeds, it's possible that you got to some implausible result that needed to be terminated, or it was really just an error. But regardless, it's not futile.

I heard you, thanks

My first CPDN workunit: I aborted it before it did its first trickle because it was longer than my patience.
My second CPDN workunit: Crashed at 300 hours.
My third CPDN workunit: Success!

And by then I already had more credits on CPDN than on other projects