Well - I've HAD to get used to the metric system - still find it odd - and all my older cookbooks and recipes are in Imperial, the old avoirdupois system. BUT, you cannot buy anything in pounds and ounces any more (well you ask, and the young person behind the counter says 'Oh yes, I'll just have to look that up in metric'... but we now have to have everything shown in only metric measurements in shops, whereas until recently, it had both.
My family all grew up only using metric - I always said to them 'what's that in 'real' measurements? ' and 'I'm sorry, I don't do 'foreign' measurements'.. we have no choice nowadays!
What I have found is that I use imperial for older recipe books and metric for new. No confusion, I just follow the recipe. I don't have to do any complex mathematical calculations (just as well really, as I am hopless at maths).
I am sorry, but most of my recent postings on here have been in metric measurements. If I use Imperial you can take it that the recipe is old....