Which promotion do you like to do, combat 1-5 (useful in any case, but only +10%) or specific ones (city raider, pinch, cover, formation, drill, ...)? At first sight, those specific ones typically +20% or 25%, looking stronger than combat. However, I heard that those +25% doesn't mean your unit gets 25% stronger, but their unit gets 25% weaker. For example, your swordsman has a natural +10% city attack, and is attacking an archer in city. This is not that you gain 0.6 strength, but that the archer's strength is reduced by 0.3. So, combat +10% is better than city raider +20%, if they already receive >= 100% defensive bonus, like an fortified archer on a hill city (+125%). I guess I will use combat 1-5 more often?