There are different opinions wether footcare should be performed on elephants or not. And its true that sometimes footcare may be overdone, which can cause problems. But such cases are in reality rather few.
There is much more common, that people who doesnt really know how to trim feet and nails, also argue strongly for that elephants dont need it. And in those cases the elephants are often so badly trained for footcare, that its difficult to inspect the feet for a visiting elephant keeper, Curator or Vet. If the elephants are not trained to put their feet on a tube, this is the first indication of neglected footcare. A welltrained elephants also bend their frontfeet backwards on command, making the trimming of the frontfeet soles easier.
Asian elephants in captivity generally needs more footcare than africans. Neglecting of footcare and lacking knowledge of how to do it, should be considered as sign of bad elephant management. When problems arise with the feet, its most often a result of long time of neglect, and can sometimes not be corrected over some days or a week. Therefore, a regulairly inspection and trimming is the proper method, but its not vise to say how often, because it has to be done when needed, and this may vary with season, individual differences, and stable and enclosure conditions, and with food changes and types of work, such as children riding operations.
Sometimes there may be an argument the the cracks in the sole is assisting the elephants not to slide in snow, this is also wrong because such cracks doesnt safely prevent sliding, the snow has to be removed and sand shall provide sufficial security. And cracks in the soles in cold climate is very bad, since theres a potential risk in the northern hemisphere that this will also result in joint problems and Arthitis. Pockets and cracks in the sole may also lead to infections.