In over 45 years of flying I never went less than six weeks' annual leave and never went more than 10 1/2 months without taking it. Most times I split it three weeks within every 6 or so months.
Sometimes when they got themselves short of aircrew through inadequate forward planning, a company would try to throw money at its crew to sell their leave back. Guys who fell for the money invariably burned out, had fatigue-related incidents, got sick, drank too much, sometimes divorced.
I have quit jobs when they would not give me leave, or tried to cancel it on short notice. And never regretted that decision. But I do acknowledge that we live in a far more dog eat dog world now, and demanding leave when due may result in losing one's job with problems finding another, better one.
No amount of money, pressure or career advancement is worth sacrificing our mental and physical health. Now, in semi-retirement, I just get by financially on what I make out of aviation. But I am healthy. In fact my main problem could be that I will outlive my savings and end up on the beach. At least it's a nice beach.