Hot water work touches more than the appliance. Tank type, gas, venting, access, water connections, drainage, water quality, and future service access can all affect the right recommendation.
A tank replacement is often the practical path when the home needs reliable hot water with a familiar setup. Tankless can make sense when the gas line, venting, condensate drainage, water quality, flow rate, and maintenance access are reviewed before you commit.
Water purification and water softeners are different decisions, but they still need the same practical planning: system fit, plumbing access, drain path, serviceability, warranty terms, and written pricing.