You might as well at least challenge every ticket you get (whether it be a parking ticket or a moving violation); almost certainly you can at least get the amount of the fine reduced. It's worth it unless your time is far more valuable to you than your money.
It depends on how much time and how much money. Time and money are the two major commodities of life. All else flows from these two.
Some people use time to save money. Others use money to save time. Right now, I'm in the latter category, though I have been in the first category at different times in my life.
Woe to the person who is short of both.
I challenge moving violations not to save money on the fine, but to reduce points and keep them from affecting my insurance, which would potentially much more expensive than paying a fine.
I rarely get parking tickets. If I'm guilty, I just pay it. It's not worth the time and aggravation to fight it, IMO.