It peeves me when people hang on to my cheques for-bloody-ever without depositing/cashing it - not naming any names here ... *cough*BC*cough*Government*cough*. The longer the money goes untouched, the more likely I'm going to forget about it and use it for some other big, fat, emergency-ass thing that comes up (like car insurance for example). Then when the person finally gets around to depositing it, it bounces. MIL Woman used to do this, but I'd rib her that if she doesn't deposit it, she won't get her money because I'll spend it all. She got the idea after a few times. =}
I know some people back date their cheques so that there's only a week or two for the person to deposit before the bank considers it a stale cheque. I thought it was 6 months before a cheque is considered stale, but someone also told me it was 12 months. And someone else said that they'll make an exception around New Year because people tend to be confused over what year we're currently in.
I also have to figure out how I'd need to do the record keeping for it. I'd need an extra column for "Actual" versus "Effective" date of the cheque.