Bicycle Mechanics - Removing splined BB - does it matter which side first?

Just wondering if there is a best practice in terms of removing BB in general.
Also, should I loosen cups on the Non-Drive Side first or Drive Side first?

Bicycletutor.com video show loosening the DS first.

Should I squirt some WD40?
Any tips?

In most cases it doesn't matter, but on some bottom brackets the right cup is affixed to the cartridge, so you're usually better off removing the left side first. It also makes sense to do the left first because it reliably has a right hand thread, whereas the right side, though usually left hand thread might be right hand if the BB is Italian or French thread.

It makes more of a difference with installation, where the right side goes to a shoulder to establish chainline, and the left as far as it goes, so going on it's almost always right first.

Squirting with WD-40 or penetrating oil should be deferred until you see if you need it. Give it a go as is, being sure to turn in the correct direction, then if it seems stuck you can use penetrating oil to help free it.

Theer is one type of bottom bracket that you should always remove the drive side first; those with plastic non-drive side cups like many of the Shimano square taper cartridges. Attempting to remove the plastic nds cup first often results in having it crack or split and makes removal of the remnants a real PITA. Guess how I know.

Theer is one type of bottom bracket that you should always remove the drive side first; those with plastic non-drive side cups like many of the Shimano square taper cartridges. Attempting to remove the plastic nds cup first often results in having it crack or split and makes removal of the remnants a real PITA. Guess how I know.

In this case would you replace the left side first?

In this case would you replace the left side first?
You mean during reinstallation? No. I reinstall the drive-side cartridge first and get it snug. Then install the plastic NDS cup and get it just snug. Finally I torque the drive side to final torque and then get the nds cup tight but not excessively so. The NDS cup is pretty much just a stabilizer and spacer and needn't be (and can't be) torqued to full drive side specs.

You mean during reinstallation? No. I reinstall the drive-side cartridge first and get it snug. Then install the plastic NDS cup and get it just snug. Finally I torque the drive side to final torque and then get the nds cup tight but not excessively so. The NDS cup is pretty much just a stabilizer and spacer and needn't be (and can't be) torqued to full drive side specs.

+1

Theer is one type of bottom bracket that you should always remove the drive side first; those with plastic non-drive side cups like many of the Shimano square taper cartridges. Attempting to remove the plastic nds cup first often results in having it crack or split and makes removal of the remnants a real PITA. Guess how I know.

OK. It is a Shimano sealed cartridge sq. taper bb. So in this case to loosen the drive side is to turn clockwise yes? I will follow bicycletutor.com video then.

OK. It is a Shimano sealed cartridge sq. taper bb. So in this case to loosen the drive side is to turn clockwise yes? I will follow bicycletutor.com video then.
Unless you have an older or very upscale Italian frame, your bike is "English" threaded. In that case the drive side cartridge is removed by rotating it clockwise as you said.