Once a week
So others use the 90 cycle too! We do one 90 a week for dish-cloths, tea-towels, oven gloves, napkins and table linens - it all goes into the Zanussi top-loader with a pre-wash and long cycle. I use Persil NB, some oxi-white and own-brand fabric conditioner (Tesco blue at the moment). It takes about three and a half hours, but everything comes out spotless.
Everything else is done as follows: whites (shirt, sheets and 'foundation wear' - love that term) at 60 in the Hotpoint TL, Persil NB and with or without heater (45 mins without, about 55 with so depending on how much time I have), brights on 50 or 40 and colours on 30 - all with Persil Colour liquid. Again, I use the 'economy' setting which bypasses the heater, and just takes the fill-temperature to knock a few minutes of the cycle time if I'm in a rush.
The only stain the refuses to budge is iron staining from a disastrous period when our well-water conditioner failed - a load of nice white towels ruined. It appears nothing with shift this (bleaching, boiling etc). anybody got any experience of this?