When I worked for Digital Equipment Corp. I was a field service tech for PDP 11/70s and VAX machines. These were their flagship timeshare 32 bit machines. To add 256K.. might be a 6 month wait for an order to get completed and shipped for more memory. Then: First we'd have an environmental specialist check for enough computer room power and air conditioning BTUs. Then We would go in on a Saturday, the Computer Ops guys would come in and shut down the machine. We would all be on time and a half. ( ) We'd roll in and bolt up a new metal frame cabinet onto the 5 or 6 frames already full. Then we'ld install the power distribution module at the base, then we'd have to run all sorts of ribbon cable and install and entire box with a backplane and fans and all of that.. maybe a couple hundred pounds and at a cost of upwards of $10K at 1980 dollars. Then we'd spend a couple hours running diagnostics. Then the Comp Ops guys would bring the machine back on line. If we got in at 8 in the morning, we might be finished by 5PM. Buy a couple 6 packs on the way home. 16G for a Windows 10 machine to make it "snappy". Things have changed a lot! Man I'm ancient!