Gail asks: "We are redoing our kitchen. I have taken the drawer fronts and sanded down the wood portion of it. We didn't stain it, we just varnished and I've got matching knobs but will this wood turn dark over time as it has in the past?"
There are a lot of reasons why wood might go dark, the most common one is simply dirt. If in fact you have a washable finish over the wood, then it is not dirt. If the finish is somewhat permeable, like some varnish or lacquers, then grease from hands could get through the finish. Polyurethane in the kitchen is one of the best barriers between you and the wood to help keep them clean.
Then despite all the surface barriers, some wood will turn dark just from light exposure, but usually problem drawers or doors have colour changes because the back side of the wood is not sealed. This allows anything in the air to work it's way through to the underside of the finish. Ammonia vapours for instance will turn oak almost black. So -- always seal all surfaces, inside and out, of cupboard doors and drawers. And don't clean with ammonia based products.
If you can't get new handles to match the colour of old drawers, try going for a contrast. That could be stained wood, or simply very different handles. If you haven't looked lately, even the most ordinary of renovation centres has a terrific choice of door and drawer knobs.