There good and bad 50% and 50%....

I am in very larger company HR (about 85,000 employees and 15,000 contractors). 

Good, you switch company get higher pay. 

Bad, you switch too soon.

The statistics shows, average American switch job in 3 years.  Your job history that your personal DNA.  Future company may not hire you because you will not stable with a company.  If I read your resume, I will not hire you for this reason.

As I said, 50%/50%, you balance good for your 1.5 years, you narrow your future....