Notebook Hardware and Upgrade Questions

The cover to my laptop that I purchased in Sept 2017 is now cracked in 3 places.  To me, that means the case is of very poor quality.  I use the computer at home mostly, I take it to the coffee shop in a backpack designed for laptops with not much else in the backpack.  I don't think it has had beyond light wear and tear and it is already cracked in three places both top and bottom and it is less than 2 years old.  I am a freelance writer and researcher so I have to have a reliable machine. I am not happy that my computer is 18 months old and now it needs replacing.  I can't even take purchasing the computer off my taxes as a business expense because the IRS expects computers to last more than 1 year and that a new computer every year is not justifiable.  cracked underneath as screw close to frontcracked badly back of screen (this is most recent)cracked underneath near media cable port (this is the first crack to appear)