Cracks occur because the skin is dry (xerosis); this is a problem usually associated with older people but can be as a result of other skin conditions. So dry skin redisposes cracks and moisturising the skin helps to prevent cracking.
https://www.nhs.uk/conditions/emollients/
This paper might be of interest:
White-Chu, E. F., & Reddy, M. (2011). Dry skin in the elderly: complexities of a common problem. Clinics in dermatology, 29(1), 37-42.