It's no secret that once a recession hits, such as during 1999-2000, or 2009-2010, quality companies are on sale just like other companies. For many companies, one could argue that a general downturn is the only time when the company is actually undervalued, or fairly valued, barring something truly devastating that's company-specific.
Many excellent contributors and writers share with them their buy lists for a recession. Companies that belong to this category - companies that are time-tested, recession-proof/resistant or in such a business that they're virtually guaranteed to outlive all of us - at least