Software Engineer, use it partially for private and professional purposes. In historical Order: Thinkpad X201, Then a Thinkpad T450s, currently a Macbook Air M2, usually in the biggest configuration. Usually I use it about 7 years. Not because it doesn't work anymore, but because it gets too slow for what I am doing with it. In one case it was the switch from C++/C# to Rust and the compile times became unbearable. The next switch might be because of LLMs.