In pve, yes if you are planning on fighting lots of silver mobs, vets and champions. In pvp, not so much as only amateurs don’t cleanse conditions often.
In general no. Runes of the Nightmare from TA and or Lyssa or a combo of is the standard.
I really feel mesmer benefits little from cond duration unless you’re going glamour. Shatter spec’s get duration from clones staggering in.
I run a 20/0/20/0/30 build with Carrion that get’s some cond duration from spec.
As someone said above PVE more so because of mobs general slow attack speed. Though I wouldnt recommend cond spec’s for pve period unless it’s Rampager gear.
The best thing you can do really is test it out for yourself.
I currently run with 2 x mad king and 4 x lyssa in pve with 20/20/20/0/10 and it actually makes confusion useful in PvE. Especially with scepter. Also it allows me to stack vulnerabilty and bleeds higher and makes my cripples etc longer. Because altogether i have 40% longer condies with 73% longer confusion. I use the vuln sigil on my staff and MH sword (when I switch out scepter) to bring vuln up to 50% longer. Works pretty well I think.
This is just with zerker armour and currently valk jewellery. Working on making those carrion to raise my condi damage a bit. I mostly have the condi duration for the non-damaging condies but the confusion is really nice too as extra bits of damage.
A bit of condition duration on runes is advisable in a glamour build to hit the 10 second cap on confusion duration from glamours. Other than that, it’s generally not worth it. You can find a more detailed discussion of the 2 in one of our recent Mesmer podcasts actually, from the link in my signature.
Ty for all the replies.