"relentless days" is a correct phrase that can be used in written English.
You could use it to describe a challenging period or situation. For example, "The past few months have been relentless days of hard work for everyone on the team."
The apprentice told him about his work, the relentless days of it, how even though he felt he was doing good things for people, nice things, there was no shine to his days.
I, of course, wish I had a quick fix to get through those relentless days.
It's a Category 3 climb, the penultimate of this relentless day before Jenkin Road.
Those engaged in another relentless day of buying and selling across the capital may not have noticed, but the two people who opened trading yesterday were veterans – and both were given a helping hand by the charities being supported by The Independent's appeal for Homeless Veterans.
2015 marked the second year of Secret Solstice, Iceland's first ever annual outdoor international music festival (say that five times fast), and while it became painfully obvious over three days of relentless daylight that the festival is still experiencing growing pains, it's easy to speculate how Secret Solstice can grow into one of Europe's premier summer festival destinations.
The pace is relentless: seven days a week.
"And because film schedules are so relentless — six-day weeks and crazy hours — you are in constant fear of your vocal cords packing up.
At the other end of the price scale is the Haglofs OXO 70lt Expedition Rucksack, which will withstand relentless multi-day treks and provide endless comfort through the Instant Adjustable System, allowing the bag to be tailored to the wearer.
On one occasion, six Polish divisions trapped by encircling German forces were forced to surrender after a relentless four-day bombardment by StG 51, 76 and 77.
Many Iraqis and analysts expect fresh torrents of public unrest as that deadline passes early next week and another scorching summer settles over Baghdad, with relentless 120-degree days magnifying outrage over a power grid that delivers just a few hours of electricity a day.
The relentless chatter for days on end only compounds the problem.
