Is my market big enough?
This depends on factor such as competition and on the number of business in the catchment area. Because each area has unique factors, one method of determining viability is to decide on how many fully booked trucks you require then through market research determine how many customers would be required to generate this level of volume.
Some areas will have many large potential customers, so fewer will be required. Anecdotal evidence suggests that a city with a population of 250,000 or more is quite easily able to support a mobile shredding company.
In cities where the service has been on offer for the longest the number of trucks per head of population is the greatest, with Toronto for example having a ratio of approximately one truck per 40,000 population (2.2m population / 55 trucks). In smaller cities the catchments area may be wider and require more traveling between customers, however this is often balanced by less competition and so a greater margin per unit shredded.