The memory cards have a limited number or read/write cycles, so yes, using it non-stop will wear it out faster. How long it's expected to last, check the manufacturer's specs for your card.
Phone shound not get "too hot", but will warm up due to CPU use, it should not do anything bad to the phone, but is not exactly good for it, so life span has a chance of shortening.
Lets say its a Transcend Memory Card MicroSD 32GB Class 4. How much do you think it can handle?
You can check the vendor's site, it's pretty much what anyone else would do.
I checked the vendor's site already, but there is only info about durability in terms of the insertion/removal cycles. There is no info about the read/write cycles. There is no info on how much data can be written to it before it fails to work.
The answer I'm looking for is: Memory cards in general can handle n GB of writes to them for n years/months before they fail.
For example: 1 GB of data can be written to a 32 GB memory card every 24 hours for 4 years after which it fails to work.
Sorry for not making that question clear enough. I hope I made it clear enough this time.
By the way, thank you for responding