Why Does Premiere Pro Keep Crashing?

I have had Premiere Pro for a few years and it constantly crashes, which was fine when I was using it for University but now I am working professionally at it keeps happening.

It happens about after about 30 mins of use (sometimes as little as 5) and it happening about 5-10 times a day. All I get is a message saying;

Adobe PremierePro CC 2017 quit unexpectedly.

Click Reopen to open the application again. This report will be sent to Apple automatically.

The laptop I am running it on is top of the range;

3.3 Ghz intel Core i7 processor

16 GB 2133 Mhz memory

Intel Iris Graphics 550 1536 MB

This is causing me a real hassle at work as I have received the job based on my video work.

Any suggestions??