Google expects pages to “be edited, reviewed, and updated on a regular basis” especially if they are for important issues like medical information, and states not all pages are held to such standards, but one can expect that Google wants information updated in a reasonable timescale. How reasonable this is, is dependant on the TOPIC and the PURPOSE of the web page RELATIVE to competing pages on the web.
Ever heard of Maslow's hierarchy of needs? It's a theory of psychology that prioritizes the most fundamental human needs (like air, water, and physical safety) over more advanced needs (like esteem and social belonging). The theory is that you can't achieve the needs at the top without ensuring the more fundamental needs are met first. Love doesn't matter if you don't have food.