I assume you're referring to Liana being unsupported by the developers, right?

To mitigate any potential issues I would suggest the setting the shorter period of inactivity for the primary key ^{around 3 months seems optimal to me}. This way either you or haeres can take the necessary actions if needed. It’s hard to imagine something so severe happening in just 3 months that would prevent even unsupported software wallet from managing the funds.