Thickness of ready-to-roll icing To what thickness should I roll out icing for covering a cake? 

I had a look at Google where values range from 1mm to 5mm. 5mm strikes me as a bit thick; and the last time I tried, I had some trouble to roll it to anything much thinner than 2mm. Any hints?
For each of my (now 16) birthdays, I've had a cake decorated by my mum, with ready to roll icing:



I just asked her. She said:


  I normally go for 4 to 5mm. Any less and it is liable to rip. 3 is the thinnest I can get it.


I think that 5mm is a reasonable thickness (I like icing) but if you can get it to 3, go for that. 2 or less is stingy!