Matthew hotel.../... verify my visa.
For the second week I'll be staying with a friend and I want to know if I need to register my visa again, as my accomodation status will have changed.
proper said, there's no such thing as "visa verification/registration". It is the stay of the person who is declared. The validity dates on the visa just tells the legality (or not) of your stay in order to be be registered.
A form is filled and provided to authorities by hosters, about your stay in the locality, by filling in the data on your passport included the Виза part there by mid-page, after name/surname/birthdate/citizenship/place of birth/passport, etc.
Many foreigners don't need a visa for Russia, yet they are declared the same, without the "visa" data on the form.
This form, where the head says: уведомление о прибытии иностранного гражданина или лица без гражданства в место пребывания ~ Notification of arrival of foreigner or person without citizenship at the place of stay

Hotels MUST declare, so of course they do it, you can't get checked in without being declared.
In practice for couple weeks you need just the initial one (in the 7 first workdays). Until the year 2006/7 I think, there where still stamps put by hotels on the back of the migration card, that were occasionally checked, for instance by airport personal, but this was phased out.
Actually I have stayed month long just with the initial registration at an hotel, and after I rented apartments with landlords who didn't want to bother to do the paperwork.
Initial declaration is important, so you are legit inside the FMS data.
there's a good reason declaration/registration of every day of a stay is futile: when you go out excursion camping. Say it's summer and you will hike Khibiny for a week. First day of arrival you go to hotel in Murmansk, get declared, then you take the bus for Kirovsk and spend one week with the tent wandering around the mountain, tundra and lakes. You can't be declared in the wilderness....