I don’t open the brake bleeder screw when I change pads on my early 90’s Corolla, neither did I on my 70’s VW Rabbit, but neither of them had ABS. If I had ABS I’d follow the directions in the vehicles factory service manual exactly, as not doing so could prove expensive. I think that’s the best advice, just do it exactly the way the factory service manual says to.
The factory service data on my Corolla doesn’t require to open the bleeder when replacing front pads. I just do what it says, step by step, move the piston as much as is needed so I can get the new pads back in. I haven’t done this job in a while, but if I recall correctly I remove the caliper, leaving the hose connected, hang the caliper from something nearby using some bailing wire so it doesn’t stress the hose, then I use a C-clamp and some pieces of wood (as a buffer to avoid breaking something) to move the caliper open. I first check to make sure the fluid level isn’t near the top of the plastic bottle, b/c I don’t want it to spill out and make a mess when I compress the piston.
A couple of hints. When doing pads for the first time, remember to only do one side at a time. Don’t start on the second side until the first side is all put back together. First, you want to have one for reference in case you forget which part goes where. Second, if you remove both calipers, and force the piston on one side, it can cause the piston on the other side to fall out, which is no good.
No harm done to take some photos of course before starting. It’s critical all of the anti-rattle springs, shims, pad support plates, wear indicator plates etc are all installed where they are supposed to go, and oriented correctly, otherwise you will be dealing with problems later.
The other problem a first-timer can experience is the piston getting slightly cock-eyed in the bore. That could cause it to stick and the brakes won’t work. So it’s important to visually check and make any adjustments necessary so the piston is seated properly in the bore before considering that side done.
While this method usually doesn’t introduce air into the system, I still always replace the brake fluid in the bottle with new, and bleed the two caliper’s I’ve just worked on so there’s fresh fluid throughout.
Edit: One more hint. On some cars the rotor can fall off if you don’t secure it properly when removing the caliper. A rotor falling on your foot is best avoided.