There are two methods repair combots; by sending damaged combots back to the assembly or using Hover Vehicles to repair them like building structures. Note: The first method may prove to be faster, but the second method can be very useful on one-on-one combat.
Build a squad of 5 to 25 Combots equipped with jetpacks and a mix of ranged and HTH weapons (for example, Katana Swords and LRM missile arms, Axes and Gattling Guns, Electro Grips and Plasma Cannons) and back them up with a couple Hoverjets and Bombers. These units can wipe out most (smallish to medium) orbital bases and ground bases. Send in the Combots first to take out any Anti-Air Turrets (so the planes are not shot down), then any other turrets, then head straight for the Matter Converter. Once this is down, the base's defense shield drops and other buildings can be destroyed with ease.
During skirmish mode on map 26 is a platform in the center of the map. On that platform is a Hedoth Combot without a crew. However, there are also 20 to 30 Hedoth Tanks. Make a huge army. Destroy the tanks, bring a Combotcrew and research the parts.