Why 'through the year' is the operative phrase
Owners often treat parasites as a summer problem, but central heating keeps flea eggs hatching in carpets through winter, worms do not follow a season at all, and ticks are active in mild spells across much of the year. Prevention works by never leaving a window: most products protect for a defined interval, and an application given late can allow a flea population — most of which lives as eggs and larvae in your home, not on the dog — to establish itself for months.
Think of the year as continuous cover with different pressures: flea and worm protection as the constant base, tick vigilance rising in spring and autumn and after trips to woodland, pasture, or abroad.
The main parasites, one by one
Fleas cause itching, allergic skin disease in sensitive dogs, and can carry tapeworm when swallowed during grooming. Intestinal worms include roundworms, which puppies acquire early and which matter for children in the household, and tapeworms linked to fleas and scavenging. Lungworm, picked up from slugs, snails, or their slime on toys and bowls left outdoors, affects the lungs and blood clotting and can be life-threatening — it is the parasite owners most often have never heard of until a vet raises it.
Ticks attach during walks in long grass and woodland, feed for days, and can transmit diseases, especially after travel abroad. Check your dog after such walks and remove any tick promptly with a proper tick tool, gripping close to the skin and twisting as the tool directs, then note the date.
Building your dog's actual plan
There is no single schedule that fits every dog, because products differ in spectrum and interval and some cannot be combined casually. Your vet will weigh where you walk, whether your dog swims products off, whether there are cats in the home — some dog flea products are dangerous to cats — whether children cuddle the dog closely, and any travel plans. Puppies need more frequent worming than adults, and a dog who scavenges carcasses or hunts needs a different worming rhythm from one who does not.
Never stack two products to 'make sure' without veterinary advice, and never use a product bought for a different-sized animal. If a treatment is vomited, missed, or applied just before a bath, phone the clinic and ask rather than guessing.
Keeping cover unbroken
Prevention fails by diary, not by chemistry: a treatment bought but left in a drawer protects nothing. Put the next due date in the calendar the day you give each application, keep products somewhere visible rather than stored away, and review the whole plan at the annual check-up as your dog's walks and travel change.
Travel rewrites the risk list, so raise it before you go rather than after you return. Dogs travelling abroad can meet parasites and tick-borne diseases they have no protection against at home, and some destinations require specific treatments documented at specific times for the return journey. Even within the country, a holiday in tick-heavy countryside or a stay in kennels changes exposure. Puppies, meanwhile, need their worming kept on the tighter early schedule their breeder and vet set, because roundworm burdens build quickly in the first months and the whole household shares the environment the puppy lives in.
Logging each product, the date given, and the next due date in KinsLe's Pet Passport builds a complete prevention history that any vet — including an emergency clinic meeting your dog for the first time — can read in seconds.