My beers benefit from secondary based on current equipment and processes.
Most of the time airlock activity is briefly noticed after transfer to secondary.
Will tighten up the headspace, and go to a full 5 gallon batch in a 5.3 speidel.
Just curious as to why your beers benefit from using a secondary? There are many reasons you may still see airlock activity after transferring from primary. One being fermentation wasn't complete in which case you are removing your beer from primary fermentation too early. Another being that what you are seeing is just off-gassing. In any case the term "secondary fermentation" is a misnomer. There should be no more fermentation going on. If there is, again, you are removing your beer from the primary fermenter too early.
Some brewers believe that there are certain situation where using a secondary stage is useful... adding fruit or dry hopping are most cited. But a lot of brewers are discovering you can make those additions IN the primary fermenter. Another commonly brought up reason for using a secondary is clearer beer. That is quite debatable. With fining or cold crashing you can achieve very clear beer with the risks associated with transferring to a secondary.
Another reason given in favor of secondary transfers is the conditioning required for certain high OG/high ABV beers. Some which are aged for many, many months. The explanation goes; you should remove the beer from contact with the yeast cake. My comeback is; so transfer it right to your keg or bottle it when fermentation is complete and let it condition there.
@goose: I use one of these for dry hopping in either my Chronical or keg... http://scottjanish.com/wp-content/uploads/2017/01/cornykegdryhoppers.jpg