Is it alright to plant a different daylily in the same spot where you have removed one? I recall reading somewhere that you should not do that with roses, because some chemicals released by the first rose will inhibit the growth of the second rose, and I thought I'd better find out if this applies to daylilies as well! thanks for your advice!

You're thinking of "specific replant disease" aka "soil sickness" which affects roses, some fruit trees etc. I've never heard it suggested to apply to daylilies, but regardless if the previous occupant of that spot died of something like a root or crown rot you may be safer not to plant there for a while, and even replace the soil in that area.

I wouldn't have a problem with reusing the same spot for a daylily, given that the previous plant was 'removed'. maybe back fill the hole with fresh soil/compost to be safe. I do agree with Sue though. if the previous plant died from some sort of disease then I may think twice about it.

I plant mine in the same spot as long as no daylily died from crown rot in that spot you should be ok. Just amend the soil a bit. I usually add a bit of compost.