Are screensavers necessary for use with the iPad? If they are necessary, do I need to get some screensaver apps?

no, they not really screen savers up here. just background wallpapers. you can pick any photo of your choice and use as a wallpaper. this is not like a pc, that uses a screensaver. thats old technology. ipad battery is more thn efficient enough not to need one.

Screen savers are also not necessary since most people have their Auto Lock time set to somewhere between 5-15 minutes and that will automatically shut the screen off. The biggest drain on the battery is the screen so it is just better to shut it off when you are not using it.

Screen savers were more put in place because screen technology may have an issue when leaving the exact same image on the screen could create burn in or a ghost of an image up on the screen. I haven't seen that issue with any new screen technologies in 5+ years. Old CRTs had the issue, old LCDs had an issue. But I've never heard of problems with iPads ips LCD screen.