Air stones should be lumped in with 'need to be replaced when clogged'. If you notice a big change in the bubbles size, probably time to swap. You can try cleaning them in hydrogen peroxide to remove the organic build up or just put in a new one.
Filters, heaters, and chillers should be fine to keep using until the fail. Filters and chillers have parts that may need to be replaced as part of regular maintenance--o-rings, gaskets, impellers, etc--but the housing should be fine so long as it doesn't get dropped and crack. Chillers, if not properly drained before storage, can also have rust issues if water sits in the lines.