The phrase "are often arduous" is correct and usable in written English.
It can be used to describe tasks, processes, or experiences that are frequently difficult or challenging.
Example: "The training sessions for the marathon are often arduous, requiring both physical and mental endurance."
Alternatives: "are frequently challenging" or "are often demanding."
The first stages of reclaiming Africa's dance heritage were often arduous.
Bruce McIver, the chief negotiator for Mount Sinai, said it was often arduous to bargain with the nurses' union, explaining that it took 25 bargaining sessions to reach the tentative deal.
Independent filmmaking quickly became a business, and woe unto those filmmakers for whom it didn't: films (which, then, were shot on film) weren't cheap to make — yes, cheap by Hollywood standards, but expensive for the filmmakers themselves, for whom the fundraising process was often arduous and protracted.
He didn't mind the apartment, which did not have a river view, but the commute by subway to his downtown office was often arduous, he said, with huge crowds and, in the summer, no air-conditioning during the wait for a train.
Given the fact that most H5N1 infections in poultry and in humans occur in resource-poor areas where access to health care is often arduous and expensive to obtain, we hypothesized that many people with H5N1 virus infection would not have been examined by a health provider to allow formal H5N1 disease confirmation.
His journey was often arduous after he left the palace.
Although this latter aim was relatively successful, it should be noted that partnership with these representatives was often arduous, particularly at the central level.
Major breakthroughs in such a process are often engineered in arduous all-night negotiations, with the psychology of political pressure as a key factor (e.g. [7]).
Since forest extraction activities are often tedious and arduous, young people have an upper hand in collecting more forest products and sustaining the collection activities for a period of time compared to the elderly.
The model aims to enhance existing manual scheduling and timetabling approaches that are often accompanied with arduous combinatorial tasks such as resolving class conflicts, dealing with parking and traffic congestion, and ensuring an efficient utilization of facility and human resources.
