1. A good office chair
Sitting in an uncomfortable chair all day can result in back pain and distract you from concentrating on your job tasks.
A decent desk chair should provide lumbar and pelvic support to remove stress from your back muscles. Since poor posture may lead to headaches or muscle fatigue, a supportive chair is a worthwhile investment.
2. A desk planner
While I often use Google Calendar to note important dates and there are no shortage of online planners, it also can be helpful to have deadlines, appointments, calls, and other reminders written on paper as well.
Keeping a written to-do list near your desk can help you stay on-task, remind you of what's coming up, and help eliminate the possibility of a scheduling error.
3. A wireless printer
While mostly everything is done online these days, from shopping to filing your taxes, there are still times when you'll need a printer.
Going paperless is great for the environment, but when you need to print out a form to send to an employer or you prefer editing with a paper and pen, a wireless printer comes in handy.
A wireless printer also means one fewer cord to get in the way. Plus there are some inexpensive, high-quality options out there.
4. A filing cabinet or folder
There may be times when you'll have important documents like receipts or payslips that you'll need to hold onto for the future.
To avoid losing these documents, pick up a filing cabinet or accordion folder to keep important paperwork organized. A folder in one of my desk drawers safely holds all of my paper documents in one place, and I always know where something is when I need it.
5. An external hard drive
If you depend on your computer for most of your work, then it's important to back up important files and documents in the case your hardware fails.
External hard drives these days are relatively inexpensive for large amounts of storage space, like this external drive that gives you 2 TB of space for about $60.
You can also opt for a cloud storage service like Google Drive, DropBox, or iCloud, but I'd still recommend a physical external HD just in case you were to ever lose access to your online accounts or should you need to access your work when there's no available internet connection.
6. A phone charging cable
Even if you work in an office where using your phone during business hours is frowned upon, the truth is that things come up and an emergency may arise where you may need to reach someone quickly.
You don't want to get caught with no power in the middle of your workday in case the need arises, so it pays to keep either a USB or wall charger at desk at all times.