When I first speak to a client about redesigning their garden I always ask them to be honest about how much time and money they wish to spend in their garden,
Dahlias are on my high maintenance list and I would not recommend them to any client who is not willing to put in the time. The combination of staking/feeding and dead heading plus the pests that they attract requires some effort.
Although I am based in Cornwall which is milder than most areas, the above average rainfall that we experience means that dahlias are prone to rotting if left in the ground over winter, so I prefer to lift them and store them in the greenhouse, this also means that they get a head start in spring.
Some of my clients who are more affluent seem quite happy to use them as disposable bedding and they are willing for the local nursery to do all the hard work, which is another option.
Anyway I wish you all good luck with them next year.