Blogging this as a simple reminder to myself on the default (out of the box) value of the Search Service Application index location in SharePoint 2013. Invariably I have to look this up every couple of months when supporting customers and only ever find the PowerShell commands to retrieve it. Putting both on here. Hopefully this saves someone else a few minutes of their day as well.
$ssi = Get-SPEnterpriseSearchServiceInstance $ssi.Components | Select-Object IndexLocation
C:Program FilesMicrosoft Office Servers15.0DataOffice ServerApplications