The existence, or otherwise, of a will is not relevant. The Probate Calendars include grants of administration - the legal process required to deal with the estate of an intestate next of kin. What did (and still does) matter is the nature and value of the estate. If a person left only a small amount of cash and personal effects of limited value, there would have been no need for probate, irrespective of whether they made a will. Most of the factors that now trigger probate (property ownership, money in bank accounts, share ownership, pensions etc) were reserved for the middle classes and upwards until later in the 20th century.