Not only did you have to worry about IRQ conflicts, some hardware didn't work well (or at all) at some of the offered IRQs. And there was no Google to help you.
Indeed. I remember cycling to the local library, searching the old serial terminals for a particular book that could explain an issue I was having, then order it to be sent to my local branch (as they invariably didn't have it) so I could pick it up a few days later. Just to solve a problem (usually pretty complex ones involving things like datasheets or programming manuals but still...).
The internet has provided us a way to handle much more complex issues in much less time just by offering immediate access to shared knowledge. That alone makes things much easier these days than back then.
But I feel it makes us dumber as well in a sense. Before the internet you couldn't start a major project without knowing all about it before you started. Now often we will just start, and google any problems on the way, often realising only later on that the initial approach was poorly chosen.
I can still remember with horror a Windows NT networking class that needed every student machine to have three ISA Ethernet cards manually configured with non-conflicting settings.
Can you have that ready by tomorrow, they asked after lunch...