Keeping "Bad" Strat vs constantly retraining (in General)

a) Get a decent strat and keep it regardless how the rest of the CB world change and your only modification is what weapon/armor you use and minor changes by altering the proportion of XP you put in each skill/ability.
b) Retrain every changemonth to make sure you have something that is broken in half, or at least close to it.

In the long run, which plan will give you higher MPR? Plan a because you don't lose XP to retrain or the higher challenge bonus you get by adapting?

is this from an n*b point of view or a non-bonus character?

I would think that retraining much less benefit especially because there is inherent risks in retraining anything if you don't achieve the higher CB% you thought. However I think in big changemonths it is probably necessary to modify somewhat. I have always just done the xp distribution differently to react to changes.

Way too circumstantial to be able to answer properly, but I'll try anyway to give a guideline :)

On a character without a bonus, partially retraining is a good option, since it allows you access to targets you would have had absolutely no chance to get access to otherwise, so the drop in MPR will be eventually counterbalanced by the increase in challenge bonus (well, depends here too just how big the drop and how much higher the bonus, and how long between retrain cycles, but you get the idea - also, it keeps your tattoo slightly closer to MTL this way).

With a NUB/NCB character, it's better to stick with whatever strategy you have going after the first few days/weeks of play with that character. Retraining is counter-productive because not only do you lose time out of the heavily bonused time you will never get back, but your target selection will be changing almost completely sooner rather than later because of your fast growth, you WILL find big challenge bonus targets eventually, and leave them behind a while later... so retraining in order to beat some specific strategy after the last changes, that's simply unnecessary.

I would point out that if a retrain offers you a more than 10% boost in chal bonus and you've got a lot of N*B left a retrain would be a good thing.

score > mpr

fun strategy > boring outdated one