Battery, starter

I have a 1998 Grand Jeep Cherokee, 170,000. Haven't driven it much lately and one day the starter didn't turn over as if the battery was dead. I called for a jump and the car started. Drove it a little only and week later had to jump it again, this time had a mechanic charge the batter (which is a year old.) Two days later, after no driving, it only made a clicking sound. Thanks for the advice.

Kirk