1.  If you can't play anywhere from the gutter to 4th arrow, having a big arsenal won't help you

2.  If you can't hit the pocket with every ball in your bag on most conditions, balance holes aren't going to help you

3.  Taking 4 or 5 balls to league on a house shot is like taking 14 clubs to a pitch and putt

2handed and juggernaut  absolutely nailed it, my same exact thoughts; Let them use their 6-8 balls all over the place and still can't reach the pocket, while us knowledgeable bowlers (regardless how many we bring)   play where the shit allows, and make our proper adjustments first and continue to score our lights out (ball change is the last resort)  and they can stay in no man's land and bitch and complain. 

Who's the dummy now?

 
What I bolded in your response above is what's key to some of the pushback here. Playing the sweet spot is a given. But sometimes you need more than one alternative to get the right hook shape and entry angle to keep from pinging 7's and 10's all night.

The other night was a perfect example for me. The 2 balls I use 90% of the time weren't carrying the corners during warmup. Changes in speed, line and release weren't fixing things. I tried one of the other 3 I that I bring (and rarely use) and I began striking with confidence.
 
I ended up shooting a solid 730. If I had gone with avabob's assertion that sometimes you won't carry no mater what, I would have probably grinded out a subpar 620-650. No thanks.
 
It's just a topic. Healthy inquisition and debate is good. Shutting that down benefits nobody.

Playing the sweet spot is anything but a “given.”

Perhaps #3 should be edited. I concede that it applies to the authors home house. But it doesn't apply to some of us who don't have the luxury of having a consistent shot when league starts.

Otherwise, I still say if the "correct" ball for the condition doesn't matter, why bring ANY balls to league, just take one off the rack and make your adjustments.

 
Agreed. My home house has little consistency from one week to the next. I bowl on second shift THS. Besides the challenge of old lane beds and outside weather impacts, there is the wild card of following a mixed handicap league where the oil is randomly depleted and otherwise pushed all over the place. I can't assume much at all.
 
In that world, it's better to hope for the best but prepare for the worst.

Nobody is once again disagreeing with you both; Your just regurgitating what the original post was about...   it's always good to be prepared for any condition no matter how prepared you are. That's the beauty of this game.

If you need just urethane and can adjust in all ways, great; If you need a 4-6 ball Arsenal with changing condituons8, that's great as well.  At the end of the day, having having proper mechanics, bring able to adjust, and having a open Arsenal =  bring prepared no matter the shot/condition.

We're all on the same page now, let's enjoy what the shot gives us, and go from there....