Yes you can, aslong as that alt is still existing. But its value will never be the same as before, because all altcoins price is not stable. Sometimes its increasing and sometimes dcreasing. Just hope that the altcoin you hold is profitable even if you hold it for long years.
thats right, holding an alt in your wallet is not bad the thing is just make it sure to be protected and know hows your wallet works and it will be safe always. also knowing the unexpected happenings on your token must be preferable so that in time to time you can easily adjust what you're plan.