Quick tip to avoid early retirement

Generally speaking a warrior is the only class you'd have any concerns about potentially retiring. I've had some hunters retire, but this is rare and usually involves not getting certain opportunities in a campaign, and general bad luck with an overland map (having to build lots of passes / bridges).

First off, I actually don't mind heroes retiring that much. I think it's fine to let it happen naturally, and plan for it as you go. There's also a benefit to heroes retiring especially if you bring in some legacy heroes prior. If there's a hero that's retiring early and you don't want them to, chances are they haven't overshot their retirement age by that much. If they have, well it's probably just their time and you should let them go in peace, but say you have a hero that surpasses their retirement age in the middle of a chapter. Initially you had a warrior that wasn't retiring at the beginning of the chapter, but will be retiring at the end of it. This can be an unpleasant surprise, but there's a very simple trick for getting around it.

Just have them solo scout a wilderness tile, and select option one, fighting like chickens. You're looking for bad mustard, and if you take option 1, they get a +4 to retirement age, meaning they might just last a bit longer. This is by far the easiest approach. Sure there's other methods on hand like griddlecakes, but that might be a bit trickier to activate. All you really need for this one is a wilderness tile and a warrior that's willing to scout a few more times before they finally turn in for the campaign.