If you're considering updating the look of your kitchen, replacing the cabinets and doors might not be necessary if you're willing to put in a little elbow grease. Refinishing solid wood cabinet doors can be a fairly simple project if you're planning to paint, or a more detailed and time consuming process if you're going to go with a stain or clear coat. Start by removing all of the doors and hardware from the cabinets. Like any project, the better the preparation, the better the result will be.
If you plan on painting, you'll want to give the doors a good cleaning to remove any leftover dirt or grease, and sand all surfaces with 120 grit sandpaper to prepare for priming. If your doors and cabinets have multiple layers of paint on them already, use a chemical stripper first to remove excess paint. If you're painting the cabinets as well, prepare all visible surfaces along with the doors. After filling any scratches or defects in the doors and cabinets with wood filler, sand the area smooth and remove any remaining dust before applying one or two coats of primer, followed by your paint. There are many paints to choose from for cabinets and doors - the folks in the pain department are a great place to start and will assist in choosing the right paint based on the material and your needs.
If you plan on staining solid wood cabinets and doors, you'll need to remove any trace of paint, oil or stains from the wood. Using a combination of chemical strippers and sanding, you will need to expose raw wood to allow it to absorb the new stain - this is a lot of detail work which can't typically be done in a single weekend. If you are only planning to freshen up the clear-coat, a thorough cleaning followed by sanding to ‘rough up' the surface is generally enough to provide you with a dramatic improvement.
If you're able to set aside the time, and willing to put in the effort, you can breathe new life into an old tired kitchen and save yourself a few bucks while you're at it!