Dry clean only, but only when necessary. Every six months may be enough. Invest in wooden clamp hangers, and hang trousers from the bottom cuffs to air and de-crease.
Rotate suit trousers on a daily basis. When pressing, place a dry cloth between the iron and the fabric. Or use a steamer.
Whether smart or casual is the order of the day, chinos should always be spotless.
Wash at a maximum of 30/40 degrees. To avoid marking the fabric, turn inside out to iron. Iron downwards (along the leg). This helps to maintain the length of the cloth. Do not tumble dry