Video drivers

How can I tell whether I need to install video drivers?

Normally, I just install FreeBSD and accept all the defaults, but after trying various WM's (normally I use CLI...) it seems that more configuration is required. I'm using FreeBSD 11.0-RELEASE on various ThinkPads and get inconsistent results. How do I check which video chip is present and whether I need I need specific drivers for that chip?
I've found that the Internet can be incredibly unreliable sometimes ;).... But as for FreeBSD, doesn't it identify which video chip is present when booting?
Look at the specifications and/or documentation of the laptop.
Of course, that's making the assumption the vendor page will have more than Intel Video card or whatever. It's harder than it used to be to find the model of video or wireless that a specific
laptop is using.

You can try something like Thinkpad <model> FreeBSD and limit the search to the last year or so, which is sometimes useful.

There's a command [pciconf -l -v] that should give you the make of video card. (You'll have to search for things with VGA in the name)
Most of the newer Intel cards, which is usually what a Thinkpad uses, aren't well supported by FreeBSD-11. You can usually get them working better by using CURRENT, and the drm-next stuff. I have a few
details on a page of mine on a yoga2, in the FreeBSD section, just search for drm-next on the page.

I'm making several assumptions here from your description, which has, as forums will, devolved away from the original question, but if it's an Intel card, and and a fairly recent Thinkpad, to get it working at all well, though not perfectly, you will use FreeBSD-CURRENT and follow my page and the link it provides.
Thanks for your helpful input! I was not aware of 'Thinkpad <model> FreeBSD' but it's really useful...
Having said that, I'm currently using a T420 and the Wiki says
[*]Graphics: Nvidia NVS 4200M

pciconf -lv

vgapci0@pci0:0:2:0:    class=0x030000 card=0x21ce17aa chip=0x01268086 rev=0x09 hdr=0x00
    vendor     = 'Intel Corporation'
    device     = '2nd Generation Core Processor Family Integrated Graphics Controller'
    class      = display
    subclass   = VGA
What do I do with this information?

/var/run/dmesg.boot tells me
VT(vga): resolution 640x480

This is clearly wrong, but how do I change it?
The Thinkpad model thing is just one way to search to see if anyone has written up something about using it.
The Wiki, it seems is wrong--as I've said it has become harder to find specifics about various parts online--I said the manufacturer's site, but even googling something like that, vendors change parts all the time--so you might google and see laptop X uses an Intel wireless card, buy it, and find your model has an Asus. I agree that the Internet is not reliable for things like this--nor are the vendor's sites. But I digress.

I'm not sure what video card that is. Do you have Linux or Windows on it? Either one is more likely to give a model number, Windows with Device Manager and Linux with lspci. Anyway, if the Intel driver supplied with FreeBSD isn't working out of the box, there's a chance that using CURRENT and the drm-next kernel might get it working better. I've only tried with the Haswell card though, so I make no guarantees.

Is this one of those that has an Intel on board card and also a discrete NVidia card? If so, maybe you can just use the NVidia drivers which work quite well in FreeBSD.