all tapes are play tested, meaning: they are popped in a well-maintained and functioning consumer level VCR and watched for a minute or two to spot any signs of excessive playback issues or noise. due to the volume of tapes we are handling, we are not able to check all of our tapes from beginning to end to ensure playback throughout.
VHS cassettes are imperfect vessels of video information. that's why they look the way they do and why we love them! even under the best circumstances, videotape degrades over time and the earliest VHS tapes are now passing 40 years (!) of age.
but tapes are tough little troopers! even now, most playback issues stem from the player, not the tape. many widely available commercial VCRs are starting to develop age-related failures, as most manufacturers did not envision their products being used for several decades. a dirty, poorly maintained VCR can not only cause your tapes to look like dookie, but can damage them permanently. if you buy tapes to watch them, it's worth seeking out a skilled technician in your area who is capable of servicing your machine, or buying a refurbished machine online from a reputable dealer.