Can I use the i5 3317u for five years or will it start feeling sluggish after a while? I'm a student and I'll only use it for MS Office, web browsing, Youtube videos, etc. I won't be doing any Photoshop or video editing.
If you are doing basic things like the ones you mentioned, then you should not have any issues. If you play games then that's a different issue. It can potentially become a little sluggish though as software and the internet becomes more bloated with crap that requires more processing power.