Ask HN: Managed Basic IT for Small Businesses?

I have been working in technology industry for the last 15 years as a software developer. As you know, the shops who can afford software developers, they will have a dedicated technology team to manage the desktops, OS updates, permissions etc.

I have a very dear friend and they have a family business (rental properties). When they started, they had no employees and his father could work on laptop and get the business going.

Now they have grown big enough to have several employees and their reliance on technology has increased dramatically. Luckily, their main software is SaaS based so they don't have to worry about it.

However, they still need to worry about desktops/laptops used by employees, making sure the OS is up-to-date, that it's not infected by virus/ransom ware etc, backups etc.

They are still not at a point where they need a full time person.

I looked up and found providers like http://www.redeye.tech/ and http://www.geeksonsite.com/ They look reasonable. I am wondering what other small businesses in similar situation are doing?

By nature, these IT providers will have full access on the machines, how does one ensure that they don't misuse the access to gain privileged information?