Hi guys! (jasontx glad to see you posting, thanks for the reminder on UV and plastic - welcome to the forum!! ) While I don't doubt that the wire brush is 'harsher' on the plaster (Pebbletech, whatever), it's not going to 'carve ruts' in the finish.

One thing that hasn't been mentioned is the amount of force being applied to the brush, using excessive force will wear down both the brush and the pool surface faster. Usually brushing the pool does not involve 'scrubbing', however if you have black algae scrubbing is needed to get the chlorine past the protective layer that it forms. Normal, weekly, brushing is just to expose any low 'water exchange' spots in the pool which might start to harbor algae or 'bio-nasties' to the fc in the water and dislodge anything which may have started to take hold- a quick 'kiss and promise' brushing will do this.

One of the reasons I said what I did in the earlier post is because I've seen dozens of 'crete pool owners who have used a liner vac (with the brushes on them) to vacuum their plaster pool and worn down the brushes within a month or so (then they ask me why this thing keeps needing new brushes and sometimes a new vac head because they 'ate up' the plastic where the brushes go). While I'm at it, use the vac with the wheels for a plaster pool - and if one of the wheels comes off, REPLACE IT IMMEDIATELY or you'll wreck the vac and not be able to vac as efficiently!

While it's possible that UV or other climatory degridation is going on with Vivian's brush (which jasontx pointed out), she says that she's replacing them every 4 mos. Except for under the 'HARSHEST' conditions, I can't see this as being the cause for the brush failure - I've used owners brushes that I know have sat outside for years that don't have this problem. Of course, a possible answer is that she's getting 'low quality' brushes - if that's the case, Vivian - you need to get a better quality brush, as per CrisL's suggestion.

Eh, I've babbled enough for now. In short:
Use whatever equipment and advice you feel comfortable with.

HAPPY 2007!! AND ENJOY YOUR POOLS!!