Having a liege lord not only helps you with reinforcements but it also provides you with honour every day for every city that is vassaled. Try to get someone as high a rank as possible as your liege lord as the higher the rank of your liege lord the more honour you gain every day. For instance having a prince as your liege lord when you are a few ranks below could get around 15,000 honour per day for each city vassaled. To put this into context if you have 5 cities vassaled you gain 5 times that number. It’s a big boost to your honour every day.