Ad Hoc Software Testing Does Have a Place
Ad hoc software testing is, at best, a testing strategy that is frequently criticized. In certain cases, this type of testing can be very valuable.
For example, using an ad hoc testing strategy for sanity checks can rapidly improve the efficiency of the software testing team by avoiding un-testable releases. Since ad hoc is by definition, without a plan and for a single purpose, it does require previous knowledge of the software under test to be effective at all.