Any of those choices depending on the type of relationship they have and the reason they are using them.
Some couples just enjoy using them as temporary kinky play toys to heighten their bedroom playtime. This may only last a few hours to maybe a weekend or so. Rarely is true long term chastity intended in these situations.
Others employ them as symbols of ownership or as insurance against infidelity if there is reason to believe the male may have been or may be unfaithful while away from his mate. This will usually be on a daily basis while away from home or for the duration of a business trip, basically whenever the other mate feels it necessary for their peace of mind. Some men will simply wear it as a symbol of his devotion to his mate under the same conditions.
Most often, they are used in D/s relationships where the dominant partner utilizes it as a symbol of their ownership and to encourage a greater level of submission from their mate, as long term chastity often results in the chaste male becoming not only more willing to serve his partner's every desire, but to do even the most distasteful or menial tasks enthusiastically in the hope of being granted the reward of a proper orgasm.
There are many websites devoted to chastity as a fetish, as play and as a lifestyle as well as choosing a device for your intended use, if so interested. Just 'google' chastity, male chastity, chastity devices, etc. and you will find many informative websites.