Regrowing carrots in same container

Ive never had an attack on my carrots in all the decades Ive grown them, so cannot be certain if they live there for another season.
Always grow my carrots in pots now.
I empty the old soil out and give it a refresh mixing the old soil with some new multicompost and a bit of growmore.
Always works for me and had no problems.

Was talking with some old boys yesterday, who have been growing carrots for years in pots.
They said much the same as me.
They also mentioned they never had attacks from carrot fly, not sure if its living on the coast that we just do not get any.