The phrase "is frequently required" is grammatically correct and commonly used in written English.
It means that something is needed or demanded often or regularly. Example: In the healthcare industry, proper hygiene is frequently required to prevent the spread of infections and diseases.
For example, where one party obtains property from another by making fraudulent representations, the defrauding party is frequently required to hold the property in trust for the defrauded party.
To occupy such a position, a strenuous course of training is frequently required, involving some knowledge of therapeutics (healing), leechcraft (use of leeches in healing), trephining (operating on the skull), herbs, poisons, and perhaps sleight of hand and similar techniques, together with the development of psychical and occult qualities.
Therefore again XML is frequently required by regulators.
This parallel infrastructure is frequently required by consumers before start using a paid service.
The distalization of maxillary molars is frequently required in class II non-extraction patients.
Assessment is frequently required during the workup of a patient for either of these disease categories.
Surgical reconstruction of ligaments and tendons is frequently required in clinical practice.
The development of numerical spatial routines is frequently required to solve complex community health problems.
Unfortunately, early reintervention is frequently required for conduit failure and proximal branch pulmonary artery stenosis.
CNV genotyping is often prone to error and cross-validation with independent methods is frequently required.
Mapping technologies into industries is frequently required in empirical innovation studies, but many concordances only provide coarse mappings.
