With the disposable syringes I'd be more concerned with how long before they fail to pull a vacuum and end up not drawing any fluid into them.
I used to work for Eppendorf (many years ago) assembling mechanical pipettes. Our test fixture used custom made glass syringes which had plungers fitted with replaceable quad-rings. The rings were grease daily and replaced monthly (or whenever CVs started getting consistantly out of whack).
But I'm sure you're not interested in using syringes that run in the hundreds of dollars each.