I was a lifeguard in Uni for 5 years and we have a pool, so the pressure is on LOL! I have taught all my nieces and nephews with the arm bands. I start with the really big ones at age 6 months to a year (double air chamber) and then work our way down to nothing-age 3-3.5. DS has been swimming since 6 months. He is now using the half air chamber ones (supposed to be for 4-6 yr olds) I am not a fan of life jackets for swimming. This is just me, but they are meant to be life jackets not swimming aids. They also throw off the midline balance and tip the child on to their back, and they need to practice more on swimming on their tummy. I had one niece who hated the arm bands (muscles as we call them LOL!) so she had a "bubble" it is a polystyrene bubble that is on a harness that straps to their backs, they are a bit spendy comparative to the arm bands, but brilliant as well. Swimming and practicing each day makes a swimmer. I hardly spend time with DS on proper strokes etc...just give him the exposure and each day he progresses. He can jump in and swim to the ladder by himself (doggy paddle) and get out and repeat and repeat and repeat! Lots of times I am sun bathing and he is doing his own thing. That was my goal for this age, swim alone, get out and get in pool whether jumping in or like the end of last summer, going on tummy and dropping in. We also find the swimming noodles fun and a good swim aid. Sometimes, I'll take his muscles off and we use the noodles together. I also used the words "swim like a doggy" this year and that really got him paddling more with his arms. Although he then starts to pant like a dog and then sucks in water LMAO! This winter when he is 3 yrs I will put him in lessons to help with better stroke control and technique, but these last 2.5 years have been about water fun and confidence.
HTH,
Aisling x