A crossbow spends most of its life not being shot. How you put it away between hunts, and between seasons, does more to determine how long it lasts than anything you do at the range.
Decock before anything else
This is the rule with no exceptions. A cocked crossbow holds hundreds of pounds of tension, and leaving it there stretches strings and cables prematurely, costing you speed and eventually taking limbs with it.
Manufacturers are specific about how long is too long. Ravin says not to leave one cocked more than eight consecutive hours, and never to store it cased while cocked. TenPoint says its bows are built to stay cocked through a full day of hunting but strongly recommends discharging or decocking at the end of each day, with a ceiling of 24 hours before string and cable stretch becomes a real risk.
Decock the way your manual specifies: a discharge bolt into a proper target, or your bow’s built-in decocking system. Not a dry fire, and not a method you read on a forum. A discharge bolt shot into the ground is asking to find a rock.
Clean it before it goes away
Anything left on the bow has all off-season to work on it. Wipe down the rail, flight deck, and barrel. Blow dust and grit out of the trigger housing and cocking mechanism with compressed air, easing off the pressure around moving parts. Check the rail for nicks, and inspect the string and cables for fraying. If you hunted wet weather or got blood on it, that cleaning matters more, not less.
Lubricate by brand, not by general advice
This is where well-meaning maintenance goes wrong, because the guidance genuinely differs by manufacturer.
TenPoint wants oil in specific places: with the safety in the rear Safe position, a drop on each side of the safety slide, a drop on the string latch, cycling the safety after each to spread it, and a drop on each cam where the axle passes through. Wipe the excess.
Ravin says the opposite on both counts. Do not put rail lube on the rail, and never use oil or grease on the trigger mechanism or the Trac-Trigger Firing System.
Same product category, contradictory instructions. Check your manual rather than assuming.
Pick the right spot
Two environments ruin crossbows, and most homes have both.
Heat is the first. A hot attic, an uninsulated garage in summer, or a spot near a fireplace can shift your tuning and dry rot strings and cables.
Damp is the second. A cold basement or shed will put rust on your trigger group, rail, and hardware over a few months, and you often will not notice until something binds.
What you want is cool, dry, and stable through seasonal swings. An interior closet usually beats a garage or basement by a wide margin.
Case it and hang it
Store the bow in a well-fitted case, hard or soft, then hang the case for the off-season rather than standing it on its limbs or leaning it against a wall. Hanging keeps weight off the limb tips and keeps anything from resting against the string.
Two things about cases. Never case a bow that is even slightly damp, because a closed case traps moisture against metal. And do not toss loose accessories in with it: broadheads, tools, and hardware sliding around inside will find your scope and your limbs.
Do not forget arrows and electronics
Wipe arrows clean and dry, then store them so the fletchings are not crushed against each other, which warps them over time. Check every nock for cracks. Lightly oil point threads to keep rust off.
Remove lighted nocks and store them separately, and pull the batteries from an illuminated scope. Batteries left in over a long off-season can leak and destroy the optic.
Store it secured
A crossbow is not a firearm, but it is capable of killing, and belongs where children and unauthorized hands cannot reach it. A locked case or locked closet is the baseline. Requirements vary by state, so check yours.
Before next season
Pull it out well before opening day, not the night before. Inspect the string and cables for wear, wax the string, check that every bolt and mount is tight, check the cocking cord for fraying, and shoot enough to confirm your zero held.
Strings age whether you shoot them or not. If yours went into storage with a season or two on it, plan on a replacement rather than discovering the problem with a buck standing in front of you.