2003 BMW 325 Struts

I just took my car in for inspection at the local mechanic. They noted that I should replace the front struts and rear shocks because they were leaking. He showed me that there was a small amount of fluid on one of the front struts. Isnt a small amount of oil normal? Is it absolutely necessary to replace? There is no noticible problem while driving. Thank you. P.S. It did pass inspection.