We have had a potty for about a year, all in all. We actually bought two. One was a bog-standard, cheap thing that I thought would do just fine. The second, which replaced the first, is more like a chair, much more comfortable looking and it seems to be the winner for my little one. It is her potty, rather than the potty. It lives in her bedroom and she chooses to use it whenever she wishes. I switched to this method after spending months and months trying to ask her to sit on the potty periodically through the day. Since taking a more laid back approach to the whole thing, we have had three wees in the potty within a week, two just yesterday. Something else which seems to have helped was my husband's idea of buying this book.
After reading this a few times, my daughter is now desperate to have "special princess big girl pants". So I have made a deal with her. If she can use her potty and keep her nappies dry for a whole day, I'll take her to the shops and she can choose some pants. This seems to have had an impact. Despite no consistent results, she seems to understand the concept now much more than she did before.
I'm not getting over excited though. I am staying calm and expecting nothing. Of course, I jump about and clap and cheer when she actually does something. I've never seen her look so smug either.
The only advice I will ever give to a parent over potty training is this: calm down. Don't panic because you're child is refusing to pee or even sit on the potty. Keep at it or maybe try something new. Ignore people who claim that their little darling was perfectly potty trained within a week so yours should be too. I know this a massive cliché but this really isn't a sprint and if you try and make it one, your child is going to give up well before the finish line. Good luck to all!