Restoration lasts for 6 seconds in the original game, and 8 seconds in The Titans. In both editions, units and buildings that are not attacking are healed 300 health per second. Units and buildings that are attacking are healed for 30 health per second, resulting in a total heal of 180 in the original game and 240 in The Titans. The amount of healed health occasionally varies but is never higher or lower than 5.
Regeneration is fast enough to heal almost any unit to full hit points in the allotted time. The exceptions are myth units and Fortresses that are attacking, as well as Wonders and Titans. It is also useful for healing troops in combat, prolonging their efficiency. It should be saved for desperate situations or to turn the tide of a pitched battle. Using Regeneration during an attack defending a town could be helpful if several buildings are damaged and units are injured.