I submitted my 1st of 4 yStr tests back in 2008. I had no matches with surname Sargent. I have paid for Ancestry.com every year focusing and spending an incredible amount of time and money on researching the descendants of my patrilineal 4th great-grandparent and many other research tools to find a match.
It wasn't until a 2nd cousin was tested on 23andme did I suspect a Non-Paternal Event this close and on my paternal line. It was not until 3 siblings tested on AncestryDNA was I able to determine it was on my side. It was not until this point was I able to look for another surname to make use of my ySTR test.
Since I've been burnt, it seems natural for me to have others avoid the same possibility. I believe it is prudent to establish auDNA connections with as many known relatives as possible first, and identifying possible early Non-Parental Events(NPE). No one expects an NPE with a well-documented tree, but IMO, they happen enough to take out some insurance.