Comfrey is an incredibly robust plant but giving it some love just makes it produce even more. Here are comfrey plants that were all planted at the same time (6 months ago) and are only a few feet away from each other. They were all started from Bocking 14 root cuttings.
This root was planted in poor soil (hard, crusty clay) and not given any attention. After 6 months all it has produced is 2 little leaves. If I had given it any attention - extra moisture/nitrogen/mulching it probably would be thriving just like my other plants.
Just a few feet away is another plant that is in better soil but still didn't receive any extra attention. Several leaves and growing well but nothing amazing.
And finally these plants were planted in a low lying area that receives significant moisture and nutrient run off. They are only 6 months old but easily look like plants that are a couple of years old.
So to answer the question - does comfrey need TLC? Yes and no. If you just want some comfrey to grow and don't need leaves immediately, then putting it anywhere will do. However, if you want to see all that comfrey can do then you'll need to put it somewhere nice. A perfect place can be downhill from a compost pile. It will receive nutrients that runoff the pile and will put on significant growth in no time.