The phrase 'a well-established practice' is correct and can be used in written English.
You would generally use this phrase to describe something that has been done for a long time, and is now accepted as a given. For example, "In this industry, it is a well-established practice to check the quality of finished products before they are shipped out."
Getting water to drivers is a well-established practice.
We discovered that in certain states in America, surrogacy had become a well-established practice.
"We have a well-established practice at CNN," the spokesperson said.
Although microlending is a well-established practice, focusing on hospitality alone is unusual.
Loading up on carbohydrates before running a race is a well-established practice.
Soil modification with cement is a well-established practice in the field of geotechnical engineering.
Further, although there is relatively little documentation of the long-term benefits of inpatient CR, it is a clinically well-established practice in Austria making the feasibility of randomization to a control versus an inpatient CR group questionable.
Altogether, the records detailed a robust and well-established practice of cultivating and utilizing jailhouse informants against unsuspecting defendants. .
Projection mapping on buildings is a ubiquitous and well-established practice, but doing the same for the human body, while it's in motion, is something else entirely and it seems to be the new frontier for projection mapping.
Pulmonary metastasectomy for colorectal cancer is a commonly performed and well-established practice of ∼50 years standing.
As a result of the well-established practice of depositing molecular sequences in GenBank upon publication, this database probably represents the single biggest repository of phylogenetic data in the world, making it the most important repositories for information about progress on the tree of life.
