I'm really enjoying swimming in the mornings, 3 weeks ago I battled to do 15 lengths in 30 minutes, today I did 42 lengths in 30 minutes. I start with 2 x breastroke, then 4 sets of 2 x 25m freestyle. Once I have warmed up I do 2 x 25m breastroke, rest, 4 x 25m freestyle, rest, 2 x 25m freestyle, rest and then a final 2 x 25m of freestyle. The last 2 of the 10 length set, I try to do faster than the previous. I do 3 more sets like this to total 40 lengths in 30 minutes.
Getting there slowly.