@ Richard

You've been very lucky with your laptops then - although the fact you've had about 12 suggests you replace then fairly often - possibly before they require a new battery. I manage hundreds of laptops at work which we often buy in batches of say 20.

Recently over half of a single batch's batteries required replacing within the first 1.5 years (and pretty much all of them within 2) - they were'nt not necessarily holding the required charge - but they actually reported that they needed replacing and you couldn't use the laptops without a stupid message appearing on screen telling you they need replacing. I could have just left them and hoped it was a faulty warning - but I couldn't take the risk Fortunately these were removable and replaceable by myself otherwise it would have been a real headache getting them all sorted (and probably cost massively over the odds too).

A laptop battery is normally only under warranty for a year, and an extended battery warranty costs a lot - there's probably a reason for that!!