My Dell work computer made it five years. Now the keyboard is flaky and there is no parts support any longer.

That was a decent run. The business/pro laptops have better construction and wear parts like keyboards. Mine was used continuously for five years and traveled frequently in my backpack.

You can hook up an external keyboard and mouse to save mileage on the computer.

Lenovo is the best for general purpose. You can also buy every part on their website.

If you buy a laptop with a 4 year warranty, then you can have the keyboard replaced when it breaks, although you will be out for a while. What I do is buy one a year (per purpose) and keep the old ones as backups. I haven't really had much trouble with keyboards other than breaking them myself, so I'm not really sure what you're getting at. Macs have the best build quality but fuck Apple (they are also a bit difficult to repair, but on the other other hand there's a lot of people that know how to work on them because they're so common). Otherwise, I have good luck with Dells for work, and I use Razers for gaming.

OTOH, you can get all the features you are looking for in a laptop in a desktop with battery backup. The main thing you're going to get from a laptop is compactness and ease of portability. The reason most people use laptops is they have some need to travel, and they don't want to buy two computers, which saves money. Perhaps you should look into which laptops have easy to replace keyboards and touchpads if you're worried about it. I'm afraid the problem of not having spare parts is universal.

Perhaps your not thinking about the full offering, a laptop can use a docking station and provide a more comfortable keyboard, mouse, monitor experience, yet be flexible in the event you want to use it at the park for a few hours. I use a Lenovo daily at work in this configuration, it allows me to pop it out and take it to a conference room for a meeting and then dock for a workstation experience. This isn't going to solve the issues others will point out about hardware upgrades and things like that, if that's more important than mobility then you should go that way, in fact that's how I run my home computer.

Depends of the laptop but the keyboard, screen etc can be quite easy to replace on many laptops.

What are you using it for? That should be your first question in deciding if you'll be buying a laptop or desktop.

Second question: do you like/want to do upgrades, or do you want to just buy something new when vid card dies or RAM needs an upgrade?

If you just like to poke around the internet and don't want to bother with upgrades, go laptop (or just use your phone or tablet, honestly)

If you want to do gaming, or will use it in one spot 90+% of the time, and/or you want to do your own upgrades, desktop.

(You could also consider a raspberry pi, keyboard, mouse, and portable monitor/display, but that would be more if you're mostly working in one spot but really do need to move locations from time to time.)

And always keep in mind - if the product is incredibly cheap but runs pretty well, you are what they're really selling (Lenovo, for example)

keypads are the easiest thing to repair on a laptop, just 2 screws