You need a giant amount of exp to reach lv60, but there's also a giant amount of side quests in HW areas that you could leave for other classes if you wanted to. But there are so many sources of exp, you never need to worry about saving anything. Dungeons, roulettes, challenge log, levequests, tribe quests, hunt bills, there's infinite exp from repeatable content.
Thank you, this basically answered my question My concern was indeed that I would end up losing some experience as I don't like grinding same dungeons/fates/leves as I prefer quests.