I'll give you one example Lepton,
I'm in a Z D-F, t00l is in a H-LB. Not possessing Soreyes skill and audacity with the D-F I try and sneak in a wave on t00l. After 20 minutes I've been unsucessful and he has scored a fair amount of internals. Using 5 spares I'm still able to fly at 31 as he nickle and dimes me down. If I have 5 more spares I can stay a bit longer in hopes of a "lucky" shot. If I don't have them i have to make a decision immediately on whether to run or stay as another hellbore hit will slow me enough to get caught.
Either way with 5 or 10 spares the result will be the same 95% of the time (unlesss t00l has drunk more cutty sark than usual), but without 5 more spares the affair is concluded more quickly.
The other side might be a case where a little bit larger droner, say a D5D, that has some phasers on it and a great power curb, might be able to use its spares long enough to extend a fight so that it could break an opponent's rear shield as it chases it. The D5D then could hit and run some systems and perhaps pull off a kill with 10 spares that it could not have with only 5.
It is indeed a tricky thing to balance. But perhaps we can try it sometime and see how it plays out.