Do I need to get an iPhone 5 or iPhone 6, since I have an iPhone 4?

I like iPhone 4 but don't know if I need to upgrade.

Don't know if iPhone 4 will still work in future (service and internet )?

If your not 100% sure you want to upgrade keep your iphone 4 then get an iphone 5 s/c in the future.

The iPhone 4 will still be able to get service, but eventually it won't be able to get app updates as it can't update to iOS 8. So you won't be able to get new apps or anything.

If you were looking for a new iPhone, I would get the most current version, which is the iPhone 6 or 6 Plus. The difference is the 6 has a 4.7" screen and the 6+ has a 5.5" screen.

It will work but the ios version will get old therefore you will not be able to download good apps. You will have ios 7 and apps like facebook and other social media will move on to higher ios versions

Get an iPhone 5S cause its the best
perfect screen size
easy fit in your pocket
i6 is too over-priced and not worth its features