I put medieval in quotes because I'm not fully sure if it's truly medieval, but the point of history where kings and queens ruled and a currency was established, The general timezone that most medieval fantasy books are based on...
To explain the question more, When I say average citizen, I mean both the ones living close to or inside the main royal city as well as those who live on the outskirts of the country. I found out from reading about something called the hundred-year war that heavy taxes would happen and that some villagers and farms near the battlefield would be destroyed but other than that I couldn't find much.
Would the average life change much other than things costing more?
Would they still hold the big festivals or fairs that merchants gather at?
Most of the knowledge I have about medieval times is unfortunately from video games, books/movies, and the information that I could find with google. I'm asking so a story I'm writing feels a lot more realistic than if there was a war going on but everyone was unaffected by it. I tried researching but I can't seem to find much myself.
Hi there - we're happy to approve your question related to your creative project, and we are happy for people to answer. However, we should warn you that many flairs have become reluctant to answer questions for aspiring novelists and the like, based on past experience: some people working on creative projects have a tendency to try to pump historians for trivia while ignoring the bigger points they were making, while others have a tendency to argue with historians when the historical reality does not line up with what's needed for a particular scene or characterization. Please respect the answers of people who have generously given you their time, even if it's not always what you want to hear.
Additionally, as amazing as our flair panel is, we should also point out that /r/AskHistorians is not a professional historical consultation service. If you're asking a question here because you need vital research for a future commercial product such as a historical novel, you may be better off engaging a historical consultant at a fair hourly rate to answer these questions for you. We don't know what the going rate for consultancy work would be in your locality, but it may be worth looking into that if you have in-depth or highly plot-reliant questions for this project. Some /r/AskHistorians flairs could be receptive to working as a consultant in this way. However, if you wish for a flair here to do this work for you, you will need to organize this with them yourselves.
For more general advice about doing research to inform a creative project, please check out our Monday Methods post on the subject.