As long as your quick connects are not subject to environments with excessive vibration or movement, they should always stay in place. The O-ring inside of a quick-connect usually remains in good condition for a long time, however, after many years of service the O-ring could dry out and cause a slow-drip leak. If the fitting is manufactured correctly and without defects, this should never happen.
If our fittings operate in an application like a motor home or a boat or equipment with a pump, the motor vibration could cause the tubing to gradually slip out of place. To prevent this from happening, you can equip the fitting with a locking clip. The locking clip holds the collet up so that the teeth remain pressed into the tubing at all times, allowing the tubing no room to slip out.