What kind of track are you using - flex or sectional?
For flex, the recommendation seems to be to solder the curves only, not the straights, and definitely not the switches. Depending on the temperature and humidity swings where your layout is located and the materials used, soldering everything can cause problems due to the expansion/contraction of the rails and of the surfaces the track is mounted on. And not soldering the switches make them easier to remove for repair/replacement.
For sectional, I'm not sure if there is a standard recommendation - maybe they usually are taken apart and relaid out so often that they're never soldered. Sectional track is so rigid that I'm not sure that any soldering is needed, at least for mechanical reasons, if it is securley secured.