My car has been needing a jump start for the past 2 days. I look at the battery and it is labeled Nissan and it looks really old. The original owner has no record of him changing the batter in the PDF, just that the battery was charged in 2007. I looked around the battery, but could not find a date.

 

96 - 2010 makes it just over 14 years old.
It's possible, but not likely.
It was probably replaced with another OE battery at some time in the vehicles life.

 

Just got the code off the top of the battery it is P/N- 999M1-NB35C. Can anyone decipher that?

 

P/N = part number. That is the correct battery for your car. That's all that number tells you.

 

Just get a new battery, they're really cheap and this way you know when you replaced it. You should replace every so often depending on your use.

 

as far as i know i still have the original OEM Battery from Nissan bought my car in 03 and its a 98 and i've never changed it, nor have i ever had a problem with it either

 

The OEM batteries in the 4th Gens won't last more than 8 years. I live in a relatively mild climate on the west coast of British Columbia and mine died after 7.5 years.

I don't believe there is any way that a 1998 Maxima still has the original battery in it.

 

check if your terminals are corroted, if they are just buy new ones they're only like $3 $4 for the pair. if you still need a jump its time for a new battery...