Common Sense
This all depends on several factors: Money, time, energy, inconvenience.
I currently have oak kitchen cabinets that were installed in 1987. They are in perfect shape but I am tired of the oak look. I suppose if I wait another few years, they will be in style again. I may sell my house in a couple of years, so I am willing to wait until that time to decide to keep them as is or paint them.
Nonetheless, you do have options: Paint and update the hardware, change just the doors or replace all of the cabinets.
Painting and changing hardware is the least expensive way to go, but you have to do it correctly or they will look HORRIBLE soon enough. Nice new hardware can be purchased at: 99centknobs.com. You can plug up and paint old hardware holes to get new hardware.
Replacing the doors is easy and not as expensive as replacing cabinets.
Replacing cabinets opens up a can of worms for more and more work. Because then you need to do plumbing to remove the sink and countertop on the lower cabinets. You may need to do more floor work or wall repair from tearing off the back splash and so forth. Plus the kitchen down time and eating at restaurants until you can cook again.
So, how much time and money do you want to spend on this transformation?
Anonymous
Replace them, or if the carcasses are in good repair, buy new doors.
It rather depends if you are happy with the layout - I have rebuilt my kitchen to suit how I want to use it and went for a hand-painted finish as part of the traditional 'Butler's Pantry' look.