I thoroughly clean all records, new or used. Time at the bench depends on record condition.
New lps are not clean, IMHO. Some 5 years back, I CF-brushed and then played a few high quality pressings of a well respected audiophile vinyl european label. All those records were bought new and sealed. To my dissapointment, the noise and crackle were very present. I am talking rifle fire on the speakers here
To my surprise, the label suggested that their new sealed records should only be dry brushed and never wet cleaned. This, I never could comprehend
Question: How difficult is it for a dealer or record shop to open, play, then reseal a record? That would explain the dirt on the surface and into the groove...
PS. Not to be missunderstood, all LPs were exemplary in terms of voicing, transparency, staging, frequency extention and dynamics, and I love them for this. Still, they needed a good cleaning before first play.