Welcome to the site first off.
I have done a crankcase flush once in nearly 50 years of working on cars with an off the shelf product. There was absolutely no difference in the way the engine ran or sounded after, so I would not do it again. I would recommend using a good quality oil and filter, and changing it more frequently if all you are looking to do is get the oil cleaner and remove crankcase crud that has built up over the engines life. Unless there is something specific that you want to address. I have a 1976 Pontiac Ventura that has 39k original miles, has never been apart, yet the oil is so clean that it is hard to see on the dipstick. It wasn't like that when I got it 10 years ago, but I have been changing the oil twice a year, spring and fall, regardless of how few miles it sees. It had 27k miles when I bought it on 2011.
