What does reset statistics under cellular usage mean for the iphone 4?

I've been trying to clear space on my phone because I have NO space on my phone. I have like 300 pictures and a couple videos on there… But I never really delete my messages or calling history… So is that what "resetting statistics" means? What's the best way to make space on your iphone 4?

Your iPhone has a usage counter for cellular data and cellular (voice) minutes.

Resetting statistics sets the counters back to zero. The usage counter is helpful for people who are carefully tracking their cellular usage, as they might be on plans with limits.

It's similar to the trip odometer in a car. Resetting it to zero keeps track of the usage since the reset. It doesn't change how much gas you have in your car or add additional life to your tires.

My iPhone 3GS has lots of ResetCounter logs everyday

Why would a supposedly "new i5c phone" have a date and time in the reset field about 90 days prior to the date I bought it?