I rang Vodafone customer service today to complain that their coverage is now much worse than five years ago and that I had been paying too much per month for too little, and that I was going to try O2.

Customer services asked me how long since I changed the SIM. Three of four years ago I replied. "Ahh, that might be it, you get better reception with a new SIM card."

As an engineer, previously in electronic engineering and telecoms this one floored me and I can't for the life of me think of why this might be the case, but what do you think? Any experience of this anyone?