My car won't start all the time. Sometimes it will, and sometimes it won't!

What is your question?

My car will go for days starting everytime I attempt to start it, and several times a day, but then at some point, it won't start. There does not seem to be a rhyme or reason for it not starting. I have taken it to the dealer and they had it for a week. They said that it started every single time they turned the ignition. I drove it for 2 weeks and it started many times just fine, and then one day it did not start. It's so frustrating! Have you heard of this happening before? The dealer said that they checked everything; the ignition, the fuel pump, etc. etc. but they cannot find anything wrong, and it never refuses to start when they have it.

What makes this problem better or worse?

Nothing.

How long has your 2014 Volkswagen Jetta had this problem?