OK, I know that like bonuses don't stack (except I think for luck, dodge and exceptional?). What about bonuses that overlap where the type is identical, but the '+' may not be.
Specifically I'm thinking of persuasion items which add a + to all CHR based skills. I think its a competence bonus. If I also have a +competence item for a specific CHR skill (say UMD, Haggle, etc) would these stack together or not?
My ulterior motive here is that I've a rogue and I'm maxing UMD as best I can as I level (although I have an 8CHR at this point until I find a decent +CHR item or tome). However I'm not likely to be able to get any of the really snacky and rare +UMD items any time soon so by my calculations I'm unlikely to have a UMD worth a **** until I cap and have the time to grind out for rare drops - which I will probably hate doing but might be worth it for as and when I TR - all of which will be a very long time coming.
I'm at L8 now. UMD is at 10 I think (-1 for CHR, but then maxed ranks in skill).
Standing, I reckon I can get that to 15 standing with a +2 CHR item, +3 Persuasion item and +1 voice of the master. But that's still not enough to even use a CLW wand reliably.
If persuasion and +UMD stack, then if farm necromancers doom I can get my hands on the +1 UMD gloves to take me to UMD16 standing, and then with a GH and a use of skill boost I can get that up to 22 which should be enough for 100% CLW Wand use.
Even so, what I really need at this level is CMW at min (UMD24), CSW (UMD28) ideally. And of course GH and skill boost are only temporary buffs and in the case of the skill boost highly time limited indeed. Sure I can use pots but they're expensive (they're also fast - for combat chugging pots is second only to an actual healer but for top ups between fights a wand would be much better and cheaper)
Am I right in thinking then that as you're levelling (unless of course you have a very high CHR), UMD is going to be used for getting around restrictions on weapons and wearable equipment, rather than using wands/scrolls?
Frustrating to be investing in something I'm really not going to get much use from until the character is 'finished', that's all.