I never cleaned the injectors/throttle body on my past 3 Nissan's...
- '89 240SX with about 100,000mi
- '03 Altima with about 147,000mi
- '08 Rogue with about 68,000mi... and counting
Guess what? I never had driveability issues, rough running, etc.
If you read your Owner's Manual and Service & Maintenance guide, there is no recommended service interval for the fuel injectors and throttle body either.
However, if you want the fuel injectors cleaned then get the dealer to perform the service. The commercial grade cleaner the dealer uses requires special equipment and is the only fuel injector cleaner that's safe to use. It's also sold through Nissan's tool program to the dealer.
Bottom line:
IMHO, fuel injector cleaning is not required if good quality fuel is used. The dealer offers it as a 'recommended service', but not necessarily because the vehicle needs it. There is nothing wrong with this... it's just a good sales pitch. It's still your decision if you want it.
BTW, if you think fuel injector cleaning is a DIY job... think again:
Pg 9-4 of your Owners Manual:
Aftermarket fuel additives
NISSAN does not recommend the use of any aftermarket fuel additives (for example, fuel injector cleaner, octane booster, intake valve deposit removers, etc.) which are sold commercially. Many of these additives intended for gum, varnish or deposit removal may contain active solvent or similar ingredients that can be harmful to the fuel system and engine.