First of all, welcome to Orchidboard!
Your friend is correct, and generally gave you good advice. The only thing I would change about it is that the frequency depends on the plant, and varies depending on medium type and of course the environmental conditions. My climate in the Netherlands is similar to yours (hot, sunny and dry now...) and to give you an idea, my Phals potted in bark are getting soaked every 4-6 days, whereas in a normal summer it's roughly once per week, and in the cooler months every 10-15 days. This is to give you an idea only, everyone has different conditions!
Have a look at this very good and informative thread. It's very long, but the bulk of the important information is in the first couple pages I think.
The Phal abuse ends here.
It's normal that the surface roots dry out first, and aren't cause for concern. If the roots in the pot are still green, don't water. If it's a transparent pot it's easy enough to check- I wait for the roots to turn silver, then wait another day or two to water again. Phals are much more forgiving of being slightly underwatered than they are of being overwatered.
Some people use wooden skewers to tell when to water, and base the decision to water on how damp it feels when pulled out of the pot. I've never used them, so can't advise more precisely.