I think if you don't have 10 years of experience and you are looking at jobs that require 10 years experience then you are looking at jobs that you potentially don't qualify for and in your cover letter you should address why you think your less than 10 year experience is sufficient for the position.

What kind of jobs are you applying for that require 10 years of experience? Typically those are managerial positions that require supervising other employees and have budgetary responsibilities, in my experience.

Having 10 years of experience does not mean having spent 10 years at one company. It means having a work history in the field of 10 years. I have worked for maybe 7 companies in the past 15 years, each time moving on to a promotion and staying longer and longer at each company, and I qualify for jobs that require 10 years of experience or more. In my industry 2-3 years in one position is fairly typical so it doesn't raise an eye brow. Depending on your industry they may expect more longevity in a position.

So tell us what kind of jobs you are applying for and your experience. That will help us advise you.

Good luck,
Seesaw