Potty training

I have learned a lot since I first attempted potty training Sophia about 3 years ago. The first is, don't let people make you think that just because something worked for them, that it will also work for you. Every kid is different, every family is different. Also, don't let people think your child should be potty trained at a certain age. Go with your instinct. From talking to other mothers, I got the impression that girls are super easy to potty train and all girls should easily be potty trained by 2 years old. If only I go back in time and slap myself, it might have saved an almost year long struggle of potty training Sophie. We thought she was "ready" at 18 months. She didn't like diapers, she freaked out when she went potty in them, she liked the Elmo potty we got her. So, at 18 months we pushed, let me tell you...pushing a toddler than just isn't ready is a sure fire way to make it that much harder. She would scream bloody murder if we even sat her on the potty. We gave up quickly.
At 2 the daycare had a "sit down" with me and told me they were concerned because she wasn't potty trained yet. All the other kids in the class were (class was 2-3 years). She was also the youngest one in the room. We decided to try rewards at that point. Potty treats, too bad she peed under our table and begged for her potty treat. We again were forced to give up. Shortly after the daycare asked us to send her with pull ups (those things can be the devil). Eventually, a few months before she turned 3, I decided to try a diaper/pull up free weekend. We had a long 3 day weekend. I bought her princess undies and the only time she was put in a pull up was nap and bed. It only took 2 days. She still had accidents but her sticker chart worked for that. At first a sticker for every day she didn't have an accident, after a week, every 2 days. After another week, it was a week. After a month she only went off the potty during naps and bed. 
Now, I thought she was difficult, but I recently learned just how not difficult she was. I had no intentions of attempting to potty train Bret until close to 3, but he made me think for a bit anyway, that he might sooner. I used to sit him on the potty at bath time around age 2, and he pooped on it almost every night. It seemed too good to be true (and it was). I got rid of Elmo after I realized how inconvenient a potty chair is. Sophie ended up not liking it and we bought one that clicked in the toilet that she much preferred. So when Bret started pooping the potty chair on a regular basis, I got rid of it (I was tired of sanitizing it multiple times a day). I learned he much preferred Elmo and he refused to potty without him, but he was long gone. I bought potty books, and Elmo's potty DVD, he didn't care. I gave up, but when visiting the states at about 2.5 my mom decided to try and he was doing ok, but it was random. We bribed him with toys, candy, stickers, we did diaper free (he peed on her door and her hardwood floor). Eventually we gave up again. After 3, I said ok, it's time now. We bought him super hero underwear and said ok, diaper free weekend. It worked for his sister, it should work for him, right? Ha! I can't even count how many times he peed in those. I would take him every 15 minutes, didn't matter he would still go in his undies. After 2 months I was ready to give up again. A friend of mine suggested the next time he had an accident in his undies to make sure that they got really wet (using water) so he knew how uncomfortable wet underwear are. That did it, well that and potty treats. It's been a couple months and he still had some accidents (mainly when he is having a lot of fun and forgets to use the potty).