Patent maintenance fee is the annual patent fee, which has the same meaning. When your patent is authorized, the official will inform you to pay the annual fee (plus registration fee and stamp duty) for that year. After that, you should take the initiative to pay the annual fee to the National Information Bureau (the official will not tell you about the annual fee) to maintain the validity of the patent right.
If the landlord wants to pay the annual fee himself, the payment time of each patent is different. The landlord should manage the patent payment period and pay it on time when it expires. It is suggested that the landlord can use some free task list management tools to set the reminder time so as not to forget.