I have 6 devices on my account I need to find out which ones I no longer need due to upgraded devices how would delete them
How do you know which device is the right one
Check this Remove a device from Find My iPhone on iCloud.com - Apple Support
The ones you use are going to show last time seen so you'll know they are the one you use. The other ones are probably be Ok for you to remove.
But don't worry, if you disconnect one by mistake, when you use it, it'll ask you to sign back in and when you do that you're back in the game.