This is a good laptop for casual use such as email and web browsing. The battery is reporting that it needs to be serviced and will last about an hour or two of light use. If you're comfortable opening up a computer you can save yourself a good deal of money and replace the battery yourself and have it last 6-7 hours. 

You can buy a battery from iFixit and they also provide step by step instructions on their website. 

https://www.ifixit.com/Guide/MacBook+Air+13-Inch+Early+2014+Battery+Replacement/24738

If you're interested in this computer but would like me to replace the battery then we'd have to discuss an increase in price for parts and labor.