While discovery plans are an important step in every matter, in Ontario, the Rules of Civil Procedure requirements must be followed to ensure the plan is binding.
In Coleman v. Neagu  O.J. No. 6195, the court considered whether an oral discovery plan trumped a Master’s timetable for discoveries. The parties had not signed a discovery plan, but had verbally agreed to a plan which they later rescinded. The court found that oral agreement to a discovery plan does not satisfy the rule that the discovery plan shall be in writing (Rule 29.1.04(3)). The court also found that Rule 29.1 should be read in conjunction with the discovery and examinations out of court rules (Rules 30 to 35) and that a discovery plan does not automatically supersede rule 31.04 which sets out the order for examinations in discovery.
The bottom line: to make sure a discovery plan is enforceable, follow the Rules, get agreement from the other side and reduce it to writing.