The way that the job-market functions is always in flux, but our cultural narrative is often more stagnant. There is perhaps no better example of this than how "job-changers" are perceived. Back in the day (when all of the baby-boomers dominated the work place) we valued a consistent and clear career path. These were the days where employees would get a degree related to their field, land a job in that field, and then work that job for the rest of their life. Though it is put on a pedestal, this path no longer implies the best employee. In fact, the benefits of "job-hopping" often outweigh the costs, meaning that transitioning from one job to another on a somewhat regular basis may make you a more valuable employee, despite what we learned growing up.
First off, job-hoppers learn faster. If you have learned to excel in a number of different jobs in the past, you have learned how to learn. This, in and of itself, is an extremely valuable skill. If you have been working at the same place, with the same set of regular problems, for 20 years- you’ll be really good at fixing those problems, but little else. If you have worked in 10 different places, each with a unique set of issues, you will be good at problem solving.
Think of it in terms of hard and soft skills. If you are only dealing with one job, you will develop a lot of hard skills surrounding that job. It is likely you’ll have those hard skills down more than someone who "job-hops." However, if you are constantly changing your environment, you will develop your soft skills and your transferable skills. This will make it easier for you to catch up with everyone else in your work-place, if perhaps limiting your specific knowledge.
There is also a pretty good financial incentive to changing jobs. There are more intricacies to it, but put simply- you will always be paid the current competitive salary. If you are working in a job for a long time, you occasionally get raises- but your employer won’t be as concerned with making sure it is a fair raise. There is an implicit understanding that you will continue to work for what you are being paid. When you first walk into a job, they want to hire you, and so they will pay you enough to get you on the team. This means that they will match or one-up the competition’s offer. Switching jobs means that when you get hired you get hired with the correct salary, which is often more than other employees are being paid.
If you find yourself switching jobs often, don’t get down. The world is changing, and with it, the job-market. We no longer live in a world where seniority is the end-all be-all, and your diverse skill set might be more useful than what you would get from a simple and straightforward career path. Embrace the change, and you will be happier and more productive for it!