Fiberglass is best, cellulose is worse since it can slump in the wall cavity if it absorbs moisture. Fiberglass batts will not. If your old house has backplaster, a second layer of plaster applied to the back side of the exterior sheathing boards, then you should avoid any wall cavity insulation since it will only lower the R value of the dead air space. Insulate under the attic floor instead since heat wants to rise. Keep your roof in good condition.
Water is the worst enemy of an old house.
What wood it doesn't rot just becomes a target for carpenter ants and termites. A wood frame house with a badly leaking roof can be destroyed in ten years. That depends on your home's age and style. Most twentieth-century houses can accommodate asphalt shingles. Consider a color like green or rust red.