I am a new member so if the blog below has been said before I apologise
i have the same problem with snails and slugs but I advice you all ,if you have any fauna growing in pots you need to check actually under the pot !!!,as slugs and snails will crawl under them ,also a great hiding place is under any rims around the top of the pots ,I regularly find several snails and slugs residing there over the day just run your fingers around the underside of the rim and you will easily locate them ,wear rubber surgical cloves if you are a bit Squamish lol.
one last note,you need to look very carefully as most people tend to look for rather large slugs and snails but on very close inspection you will find juinior slugs/snails no bigger than a couple of millimetres and they will be the ones munching away without you even seeing them,then you will claim you have no slugs or snails but you have !!!