Configurable gaps would be great and also multiple instances (somehow in sync? maybe?). In case someone chose a longer gap and then one instance went down. I personally wouldn't want anything below multiple weeks (at least; 2-3 months would be ideal for me).
This will be a good e2ee'd hosted service though (at least for someone like me). The problem is how to de-e2ee when the person is gone. Might be workable if the dependent receipient might also be well versed with encryption and had an open public key or so. Yeah, this is tricky.
But either way, it's kinda weird to setup something that will be sued after they are dead and that something is supposed to be maintained and kept up by them.
I decided not to monetize or host it for sale that way because I didn't want to deal with the warranty side of things through an insurance provider. The app is free to take and use or do with as you wish. Thinking of adding a longer timeframe to a new version as others have asked too.
Longer duration comes with the risks of payment going down where you hosted it. You disappear, bills are not paid, your dead man switch is now down too
Personally I'm handling this by paying my monthly hosting bill two months in advance. That gives my 2IC plenty of time to move the sites or provide access to my clients' new provider. Also the 2IC can pay the hosting bill. The reason the switch checks weekly is also to stay in sync with monthly bills paid. Nice insights and thoughtful comments. Thanks, calyhre.
Another option for anyone reading this thread is to put the switch on a different host to your main VPS or servers. Cheap hosting paid yearly in advance is one idea under a different billing account or another provider. My switch is hosted in Singapore but the majority of my sites are Australian. So if the Aus servers go down upstream it's less likely the switch will be affected. :)