Today's horse owners have it so easy when it comes to ridding their horse of worms. Just a simple paste wormer given orally once every 2-3 months and they are done. Some horse owners even use the pelleted type you add to the horses' feed. Both of those methods are a far cry from what use to be done to a horse only a few short decades ago.
I am old enough to remember when horse articles appeared in national horse magazines that promoted the use of cigars, fed to the horse to rid them of worms. As late as the 1980's horses were still "drenched" for worms. A vet would perform the drench. It consisted of about a gallon of chemicals pumped into the horses gut via a tube inserted up their nose. This was done once or twice a year. Even now I come across the words "horse drench" online and it is apparently still the common method to rid a horse of worms in some third world countries.
Thank goodness that health care of the horse has come a long way in the last 30 years. I wonder if that is the main reason why horses are now living longer?