It really depends on quite a few other things as well. It can really depend on how you use those things, and how consistent you are in their use. Sketches can be stable, yes. So can all of the relationships you mention, if used in the right way. But do your best not to mate using modeled geometry as much as possible. Especially geometry that has a high likelyhood of changing significantly or going away entirely. This means things like your base reference planes and coordinate system can always be counted on to be in the same location.
Also do your very best not to daisy-chain a bunch of parts together through relationships from one, to the next, and then the next. The more parts you're stacking relationships through, the bigger the risk of your assembly expoloding when something changes. Instead try mating many parts to a base part or preferrably to the assembly planes.
And I cannot stress this enough, use fasteners and bolts not as parts to hold things together like in real life. Add fasteners as an after-thought only. Bolts and the like have been known to destroy entire projects because things were mated to them with relationships dependent upon them. Mate the parts together by their own holes, don't add any fasteners between those holes until they are fully placed and only mate them to one of those parts.
ST9 Windows 7 Professional Nvidia K2200 & Intel Xeon "You're doing it wrong"