Measure TWICE, bend ONCE, TEST FIT TWICE, and apply with CA.
IN all seriousness, precut PE parts for a kit are easy to deal with if you take your time. Just remember to have a good grip on the part when you cut it from the sprue. If you think plastic parts can fly off into oblivion, you should PE parts go!
PE is great for parts that are too small or thin to be cast in plastic. Keeping that in mind, remember that PE parts are usually small and delicate. Handle accordingly. In most instances, PE replace will replace or augment a plastic part. This means that they're usually not mandatory.
Jeff