I use a 3 year-old laptop with 32GB of RAM, an SSD, and a dual-core i7 (U-series) processor. It's reasonably efficient. I think the amount of RAM and the IO speed of my SSD remove most of the hardware bottlenecks I face.
However, I would like compile times to be faster, I do sometimes notice applications hanging, and IntelliJ (we use Java at work) seems limited on how many projects I can run efficiently in a single workspace. I'm just wondering whether a workstation-grade laptop (Dell Precision or Thinkpad P-series) would be a sufficient upgrade, or investing in a desktop would be worthwhile at some point.