I tend to leave mults out of my builds because, in smaller builds, they eat space. However, when I start heading to four rows and beyond (especially if the rows are over 104 hp), a couple of passives or so is a must. At that point, you're not "stealing space" from functional devices...you're adding something that'll make a large build easier to use.

And of course, once your destinations for a CV source go beyond 4-5 devices on the same CV, that's when you stick in a buffered mult, usually up by the VCOs.