I once calculated the value of non-monetary donations, using a very scant minimum wage to account for time spent going Door-to-Door™, travelling to and from Meetings™ and in Field Service™, Personal Study™, Family Study™, and Meeting Attendance™.
Then I estimated cost of fuel spent in getting to and from Meetings™, driving around in Field Service™ and picking up and dropping off extra people for every damn Meeting™ (without so much as a 'Thank you', btw).
On top of that, there were wardrobe expenses - Meetings™-and-Field-Service™-only dresses and suits and shoes, coats (winter, spring, fall) and boots.
Then there was travel to Circuit Assemblies™, District Conventions™ and Special Assembly Days™, and associated hotel expenses when we had to travel out of town.
It amounted to well over $10,000 per year for our family. And really, there wasn't anything left to put in the Contribution Box™. I had been riddled with guilt over that for many years until I sat down and did that calculation - and then all that guilt suddenly evaporated.