K-files are more flexible and forgiving for highly curved root canals, while H-files are typically utilized for straighter root canals. There are benefits and drawbacks to both types of files. K files are generally less expensive than h files, but they are also more likely to break during use. H files are more expensive, but they are less likely to break and can be used for a wider range of root canal procedures. K files are most commonly used in the dental procedures.