Replacement is the answer once the tank itself is leaking, because a corroded tank cannot be repaired. It is also the sensible answer on a heater past ten or twelve years that needs a significant repair, since Wichita water shortens tank life below the national average.
Sizing is worth getting right rather than defaulting to whatever came out. Household size, simultaneous demand and recovery rate all matter, and an undersized heater is a daily annoyance while an oversized one costs money to run for no benefit.
The install includes the connections, the expansion tank where the system requires one, and a pan and drain where the location calls for it. Skipping the pan on an interior closet installation is how a failure becomes a ceiling repair.
Technician insight
Flush a new tank annually in Wichita. It is fifteen minutes and it is the single thing that most extends heater life in hard water.