Del spends a crapload of money......on old test equipment

All depends on the quality of the original components, and how the equipment has been used (hours, ambient temp, etc.)... I've got Command Set receivers from WWII that still use their original caps. Lots of Tek and HP gear from the 60's, only two bad filter caps in the last 20 years.
Those 5-tube radios had lots of hours and definitely were not designed to Tek/HP/General Radio standards ;)