They only gold box game I've played to completion was PoR for NES. That version is pretty different; it appears to be a ground-up remake. Many spells were bugged or useless. The only spells worth learning were:

Sleep
Read Magic
Detect Magic
Fireball
Magic Missile
Stinking Cloud
Cure Wounds
Hold Person

A few others had very limited utility in specific locations.

As I venture into the DOS versions of these games (specifically Gateway), I'm wondering if there are other spells I should be using or avoiding.

Does the aging from haste matter in any of the GB games? I don't think I've heard of characters aging otherwise.

I've always played under the assumption that it does, so I've always used it sparingly.
But I wouldn't be at all surprised if aging effects were never coded.

I'm most familiar with the Apple II version, I haven't tested this with the PC version. Keep that in mind.

The negative effects of aging in the form of reduced strength and constitution plus a corresponding increase in wisdom from P&P were never coded (and this is from 2nd edition rules, not first edition. The Gold Box games might have been what prompted my group to get started, but 2E was the only version of the core books in stores in 1990).

HOWEVER, your character can randomly die of old age. I can't recall if this happened in Pool of Radiance, but it definitely does happen in the Apple II version of Curse of the Azure Bonds.
Another caveat, IIRC this only happens when your characters rest for 24 hours or more, the check is made when you regain that 1HP of healing. At the same time everyone heals 1HP, if your character is over a certain age depending on race they might die of old age.
I haven't played the Apple II version in at least a decade, probably longer. I haven't booted my Apple IIGS since 2008. My memory could be wrong on some details, but that's the best I can recall.
I haven't let my characters get that old since the very early 1990s.