I just bought a new cheapy dell inspiron laptop early last year which has a 15 inch screen. I don't really take it anywhere because I tend to take my samsung tablet with me when I am out and about so I probably could have bought or made up a tower to go under my desk instead because I have basically set it up as a desktop, with a wireless full size keyboard ad a 29 inch secondary monitor. I made sure I configured the laptop so it has a moderately decent dedicated video processor (I don't do gaming) so that I could add a decent sized secondary monitor. Most laptops support a secondary monitor these days and I recommend getting a dedicated graphics card - mine is a AMD Radeon(TM) 520 Graphics with 2G GDDR5 graphics memory and it performs well (I don't do any gaming, just watch videos).
I bought this 29" LG 29WK500-P IPS Ultrawide LED Monitor from ebay and hooked it up as a secondary monitor.
With the 29 inch monitor, I can use it as a single monitor or split the screen, which I often do. With Windows 10 you can just grab a window and move it so that your mouse pointer lines up with the edge of your monitor and it will snap into half screen. When this happens Windows displays your other open windows as tiles in the other half of the screen and if you want you can click on one of the tiles to make that the active window in the other half. So I can end up with three screens. With so much screen real estate I can just grab a chart and resize it as I wish.
So getting back to your question, if you want to buy a laptop with a smaller screen that is more portable, you might consider the ability to plug in a secondary monitor when it's on your desktop.