As someone who once had an entirely indoor cat (first floor flat) who got fleas as a result of my neighbours cat, who was young and agile enough to jump out of the communal hall window! I now frontline religiously every month and spray Indorex once a year. *touch wood* my boys, who are indoor/catproof garden, have never had fleas and I'd like to keep it that way! It was a butter to get rid of them and obviously not nice for Tiggy, not to mention me as the little butter were biting me!
I admit don't worm as often as I should but due to their limited time in the garden and catproofing they've never caught anything so *touch wood again* they've never had worms.