Is it recommended to have more than one administrator on a company’s social media page?

I believe that social media pages must have 2 administrators, the first will be the principal and the second the assistant.
The reason is simple I believe that a companies social pages must always been updated and attractive, as to keep the interest to it's guests.
If the primary user is not able to update the page, should continue updating by the assistant.
I do not like pages that are updated every month and look abandoned.

It depends on the client/page/brand.
If you're outsourcing social media, it would be preferred to give the team (whether one individual or more) to be able to provide support for the client and the pages needs.
It is about being 'social'.
At the same time, each page should have a clear set of guidelines about posting, replying, etc - who does what, which admin is taking charge of monitoring for example.
That way everyone is on the same page.
Pages with larger fans require more support than say pages with 1000 fans.

It depends on the number of Fans and Engagement.
If you have a lot of Fans then of course one admin can't control .
For Example replying to every Fans Comments , questions about the product and services.
It will be difficult for one admin.
You need have more than one admins.

I agree with the fact that this is a very sensitive issue.
As an advocate for consistency, I think that one fully trained and capable person would be best in handling a social media account.
Having one person monitoring a social media channel enforces the consistency of the tone and the language used.
But I guess for big brands this one person approach wouldn't be viable - this is where you would need to come up with a plan and a set of guidelines to coordinate the work of a team of administrators.

I believe it depends on the nature of activities on the social media channels.
Even if you are handling masses doesn't mean you need another administrator, it always depends on the strategy in place to monitor rather handled by 1 or many.

A page can have as many admins but the important element is to ensure that only 1 person is responsible to upload content on the page.
At times a brand team requires the Brand Manager, Asst.
Brand manager, Marketing manager or sometimes senior management to have page under their administration.
Not everyone should be allowed to make updates on the page, which will ensure a consistent theme and communication style is adopted throughout.

I believe it is better to centralize activities as it is easier to track and build connections.

I believe it is recommended, as i don't think that only one person can handle a social media page specially if we are talking about a 1m+ page.

There should be a clear plan that everyone in the teams follows, however, personally I prefer one admin for each account.

Be it outsourced or in house, it is recommended that there be one central person to monitor and administrate the page, known as the Manager Admin Role.
There can be others who would be responsible for creating content (Content Creator Admin Role), for moderation (Moderator Admin Role), responsible for advertising (Advertiser Admin Role) and someone just to analyze the insights (Insights Analyst Admin Role).

You can have only one Administrator who is responsible for posting, however you may have a whole team responsible for: developing content plan, monitoring and analyzing.
If you have a bigger account with an on-going interactions with followers, you may need more than one Administrator to monitor users activities and respond when required.