Surface Pro 5th Gen Battery Life

My Surface Pro Battery is losing its charge at an increasing rate.  Advertised at 13 hours and now I can only get 2-3 hours of useful computing time out of the battery.  I am not using software that I feel should be suspect (Quicken, Edge, Excel, Word).  Does anyone have any ideas....I cannot believe I need a new battery after 3 years!

Thanks!