My goal is to set up my services so that they can mostly live with limited connectivity. Because either my phone has no internet or my at-home ISP craps its pants, but either one will happen sometime.
So it's more about being able to gracefully resume than "perfect access".
In other words: if something stops syncing or I can't access some specific service that's mostly acceptable to me. What isn't acceptable is if the syncing got into a state that needed intervention to fix or one of my services didn't come back when service is restored.
So in a sense resilience is more important than 100% accessibility.
The small number of exceptions (mostly password saves and other minor bits) I make sure to actively sync to my personal devices so that if my selfhosted stuff goes away I'm not 100% stranded.