Hi Mansfield! :-)
I agree with Cindi here and the article she referenced is invaluable and should help you quite a bit!
Your best bet, in my opinion, would be to contact an experienced REALTOR, who can many times refer you to an honest,knowledgeable appraiser or other professional that will be able to help you determine your updates values, as far as resale value goes for those updates.
If you are planning on selling the home in the near future, you should be very careful not to OVER improve your home thinking that it will add value, when it can actually hurt your properties value, ( due to extravagant updates that maybe YOU feel may look great,but a prospective buyer may not, etc...) by both making the home only appeal to certain types of prospective buyers, as well as not be comparatively priced to be competitive with other homes in your area, which is VERY important for you to successfully sell the home!
That is where a REALTOR is key for you, because they can give you a CMA (Comparative Market Analysis) for your home and help you determine the values of such improvements, dependant on todays market or whenever you wish to sell the home.
Good luck in All you do!