I am still using several T61 and T420 for web browsing and light work. Compared to those thin and flimsy modern ultrabooks those the old T series are almost indestructible.
And if something breaks you can easily replace everything with a screwdriver and cheap replacement parts.
And service manuals. Don't forget that at least for the business lines Lenovo seems to have great availability of service manuals (pcsupport.lenovo.com)
And if something breaks you can easily replace everything with a screwdriver and cheap replacement parts.