I apologize for the noob question, I have owned firearms for over 21yrs and have never had a desire to change out sights. Now that I own a M&P Shield and a M&P 40 and have read all the posts about all the great sights out there, I'm thinking about changing the sights. My question...is this something I can do myself or something I should take to a gun shop? Thanks in advance for any advice.