Conditioner

Yes, if you wash daily. It's the mask you shouldn't use daily, not the conditioner.

No. It weighs roots down and, on an oily scalp, brings the next wash forward by a day. Mid-length to ends.

If your hair is coloured, heat-styled or dry — yes, weekly. If it's healthy and untreated, conditioner alone is genuinely enough.

If your hair has been bleached or repeatedly coloured, yes — it's repairing structure rather than coating the surface. If your hair is simply dry with no chemical damage, a good moisturising mask will do the same job for less.