You can't work* on a 13" laptop, and by extension, not on a 14" either. You can work on 15", but 16" is better, and 17" is probably the sweetspot, even if there are some tradeoffs at that size.
*= by work, I mean stuff that you can't do on a 13", but that starts to become possible on 15" and larger. Stuff that some people claim to be work, and that CAN be done on a 13", I claim is not work, whereby my general statement above holds up. [intended as light humor, that is nonetheless true.]