"high level maintenance" is correct and usable in written English.
You can use it to refer to a type of maintenance that exceeds the standard level of upkeep or repair. For example: "High level maintenance is necessary for the smooth running of our production line."
But you know Katie's highlights and other accouterments require a high level of maintenance".
"Bare down there" is a fashion amongst some groups right now and may pass once people get fed up with the high level of maintenance".
The hope for anyone who needs to create a sense of structured information will be the adoption of a tool that doesn't require a high level of maintenance or the migration of data from one location (or app) to another.
Since then high levels of maintenance have been, and still are, necessary to preserve the buildings of the castle.
Or in a more sophisticated environment, a gentleman's club for example, the high levels of maintenance required to intensely condition, blow-dry and style the nail hairs will impress any suitor of a higher calibre.
Newell kept the perennial rye grass, for its wear tolerance, then examined which of more than 100 varieties best suited the high level of Wimbledon maintenance.
In the recent years however, a few studies have reported a relatively high level of weight maintenance.
Chareonsuk et. al (1997) considered a situation where preventive maintenance cost is not high, so in order to keep the system at a high level of reliability, the maintenance department decides to run maintenance programs very frequently.
"Everyone should be allowed to access the highest level of maintenance loan.
The extended flying standard, known as ETOPS, originally stood for extended twin-engine operations and established a higher level of maintenance and operational reliability for twin-engine planes flying over the Atlantic Ocean.
