At minimum you should have your home checked at least once a year. Termites have broad, thick waists, whereas ants have narrow, thin ones. Ants' antennae are bent at right angles and are elbowed. Termites have slightly concave antennae. Ants have three distinct body parts.
Termites have what appears to be two, the head and body.
So when you see one roach, chances are there are many more that you cannot see. We use a variety of products that while extremely low in toxicity are very effective in Eliminating roaches. Baits which the insect eats, Insect Growth Regulators which prevent immature roaches from reproducing and sorptive dusts that abrade their outer covering causing them to dehydrate and die.