you have a fully functional iPhone that has the entire Apple App store from which to choose from 425000 apps.
How many apps do you need?
As already mentioned, a fully functional phone with support from Apple.
Jailbreak and you lose the Apple App store, lose any warranty support and run the risk of "bricking" your iPhone.
Unless you are really desperate for a particular function on your iPhone, one that is not available at the App store, then don't do it.
I'm 70 and have some computer savvy but not a lot. I have an iPhone4 and a friend recommended I get a "jailbreak" program to download apps to my phone. Is this a legal program and will it hurt my phone if I install it?<div style="background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 191); border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px; border-style: initial; border-color: initial; color: rgb(0, 0, 0); margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; font-family: arial, sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; height: auto; line-height: normal; text-align: left; width: auto; direction: ltr; z-index: 99995; background-position: initial initial; background-repeat: initial initial; "></div>