I tend to agree that it's nice to be able to shoot what you own. Having said that, there are some guns that have historical value that would be degraded by breakage and 'lost' as a result. There are plenty of similar, but less significant, weapons out there to shoot.
I believe the Luger to be a well made and strong weapon. The point to remember is that these guns range from nearly 50 to over 90 years old. Metal can degrade with age and who knows what abuse has been inflicted in the past ?
There was a post on this board recently that surveyed the most common breakages when shooting Lugers, you might want to try a search and read that.
Other than that, it's up to you to judge if you want to turn, say a $1000 investment, into $700