I have been using 2015 Mac laptops for the past 4 years now and have not had any need to upgrade past them. For my needs the 2015 work plenty fast enough. All my 2015 laptops are BTO/CTO models fully spec'd. I have 1TB storage NVME drives in my 11-inch Air and 13-inch MBP and on my 15-inch DG MBP I'm using a 2TB NVMe storage drive. All laptops have been updated with MacOS 14.2 using OCLP 1.2.0 so I also get updated security patches for my computers and am able to use them for several more years. Once Apple stops all Intel support I may revisit the idea of upgrading to Apple Silicone. Only time will tell . . . for now I'm happy with what I have.