Why is it better to only dehydrate one hand at a time

I don't think it works like that dawg

Well if your talking about what I think its because it will lead to dirty and unproperly cleaning and care of nails. Also here's some other titles that may help you

(“One of the most common mistakes nail technicians make in nail preparation is … is not being used to clean, dehydrate and prep the nails before application)

(Most experts recommend that you use Nail Dehydrators and Non-Acid Based Primers. They are generally safer and less harsh on your nails.)

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.