Wood shafts offer distinctive feedback and can be serviced, but they respond to humidity and temperature. Stability depends on seasoning, grain, taper and storage.
Inspecting a shaft
Ask about species, drying and finish. There should be no cracks, open joins or abrupt diameter changes. Attractive grain is not proof of straightness or quality.
Storage
Keep the cue in a case at stable room temperature; do not leave it in a car or dry it beside a radiator. Rapid humidity changes increase warp risk.
Test
Roll the shaft on a true surface, check the joint and hit test shots. Compare a carbon alternative by feel and serviceability, not marketing claims.