Is there a rule for "some time" vs "sometime"? For example: Don’t trust your memory to recall noteworthy situations and events some time (sometime) later.
Sometime as an adverb means '"at some unknown or unpredicted time," The words some time refers to a period, either short or long, of time. It will take me 'some time', perhaps a minute or two, to replace the battery in your watch. 'Sometimes' I cannot replace watch batteries because I am out of stock. 'Sometime', when you are available I will show you how to do it.