If you want your print to have the best chance of lasting centuries, something needs to protect the silver. The sepia toning you do, BTW (assuming it's a bleach-redevelop "odorless" thiocarbamide process) is one of the most protective; the silver is coated with a layer of silver sulfide, which is as permanent as any toning you can give.
However -- there are a large number of prints still around from the early days of salted paper and albumen prints; as long as they were well washed in the first place, the small level of residual hypo that's effectively impossible to get rid of will actually give the silver that sulfur coating that protects it. Too much will destroy the silver, though, so you *do* still need to wash well.
Bottom line, if you print on RC paper, don't worry about it; the RC base is probably only good for about 50 years anyway, and the silver will easily last that long. If you print on fiber, and are trying to sell your prints, toning is a must if only because many buyers don't want prints they think they won't be able to pass on to their grandchildren; they look at the longevity of oil paintings from the Renaissance and the way those artworks have escalated in value, and think they're putting away their grandchildren's retirement.
A very light toning in highly dilute selenium will protect with little or no change in print tone. Platinum/palladium can be adjusted to give almost no color change from most warm to neutral prints (though it can get a little teeth-gritting when you throw away several prints, at $10 or $20 each for the metal in the toner, before you get the toning just the way you want it; there's a good reason gold, platinum and palladium aren't used much for toning silver gelatin prints).
I've got a few commercially made (well, drug store) B&W prints around here, from the early 1970s, just before RC beat out fiber in commercial processing (and a few years before color started to push B&W into the background) -- and more than thirty years on, with processing that gave little thought to permanence relative to volume, and they look as good as prints I make now (except I can't get single weight paper to dry that flat!).
I've never toned a print, except one sepia and one selenium in a college class in 1981. I'll probably get some selenium toner sometime soon, because I need it for alt-process (it keeps van Dyke brownprints and salted paper from bleaching in the fixer); I'll likely try it on my silver gelatin prints as well. Couldn't hurt...