I spend most of my coding time on just a laptop (15" MBP with 1680x1050 matte screen) and the only thing that bothers me very much is the position it puts my neck in. I try to sit lower than usual to help that.
I do use multiple desktops on macOS and a quick swipe of the trackpad to switch them is almost as good for me as multiple displays.
I do tend to use an iPad as a aux display though. Sometimes I run Duet Display to have it act like an extra display for my MBP but most of the time it's home to my distractions like Slack, email, social media, etc. But it is good for books and websites while coding.
Unless you're looking for a neck injury, you should get a laptop stand. It's close to impossible to maintain a good posture while working on a laptop over time.
I do use multiple desktops on macOS and a quick swipe of the trackpad to switch them is almost as good for me as multiple displays.
I do tend to use an iPad as a aux display though. Sometimes I run Duet Display to have it act like an extra display for my MBP but most of the time it's home to my distractions like Slack, email, social media, etc. But it is good for books and websites while coding.