You need to consider
How well does the cabinet layout fit your needs?
What is the condition of the cabinet boxes and drawers?
Are the cabinets a high quality product with lots of bells and whistles or an ordinary "builder basic" product?
Are the cabinets a unique size or shape that would be difficult to replace?

In general, I would limit refinishing to unique pieces, high end manufacturers or custom cabinetry; ordinary cabinets may not be worth the effort.

Kitchen cabinets are the focal point of the room. New cabinets will be a refreshing enhancement. I've seen refinished cabinets and personally I didn't like. If you do decide to refinish, please do your research and hire an experienced & licensed cabinet contractor. Get references too.

Ditto @Linda. Reface or replace, don't refinish.

Quote : "should i replace just the doors or do the whole replacement thing?"
Question 1: Does the layout of your cabs suit you ?
2:Does the interior of cabs look good ?
3:Are the cabs really secured to the walls ?
For us, we answered "Yes" to all above questions, so refacing was the logical choice