We have had a Wallas stove on Halcyon for six years. Since we have lived aboard more than half the time, and we have used the stove usually twice a day (for cooking and heating), that amounts to over 2,000 starts and uses.
We have just ordered a replacement Wallas. For the past year, the stove has been reluctant to start unless under shore power or engine on at high rpm. We could have some parts replaced (or cleaned) and she would undoubtedly continue to function well. But, with our liveaboard habits and often remote cruising, we want our systems to be as fail-safe and up-to-date as possible, so have reordered a new Wallas.
Just like replacing our Honda engines at over 2,000 hours, we believe our Wallas has given us good service for her lifetime and it is time for her to retire and be replaced with another (hopefully) as faithful a friend.