Sometimes leaf browning can either be too dry conditions or mineral content of water used. With my ponytail palm I just let it be, and cut off the brown tips. In time the plant grows new leaves anyways. I grow mine in a container and right now it is outdoors. It can take our mild winters here. You can repot it if you want, but do it in mid to late Spring. As drought tolerant this plant is, I keep the media very well draining so that if it rains, drainage is faster, I add pumice or perlite to my succulent media. My growing conditons here tend to be a long dry period so during those hot days, it can get twice a week watering. During winter, I just let Mother Nature handle its watering, again since our area has mild winter conditions. But if we do get frost warnings, I try to hide it overnight indoors. Since you grow it indoors, less watering for now in winter. Once a month thorough watering should be enough. Keep ambient temps as warm as possible.
