For winter grafting of deciduous trees the wood should be collected in December-January. Some late developing trees like persimmons and nuts can be harvested later. The stone fruit trees can start developing in February already. The dormant wood is required for grafting, make sure to collect these early in the winter.
Pom fruits and stone fruits can be grafted in January - March. Cherry wood does not store well and can start pushing buds in the fridge. Make sure to graft these early.
Below are the images of the same tree.
One year after grafting
Feijoa is a special case of evergreens and can be hard to graft. I had a good experience grafting them in ground in early April. However grafting later in the season especially right before the heat waves reduced my grafting success. Grafting onto the in ground trees is always more efficient than grafting potted plants. The latest trend is to graft them in February. This is my plan for this season. Feijoa wood collection and grafting can be done at the same time, regardless of the season. Feijoa wood also stores well in a fridge for a few months.
Avocado, white sapote, and citrus grafting almost always works for me, but the best time is early spring, March - April. These do not store well in the fridge, and I try to use them in under a week time.
The type of grafts does not seem to influence my success rate. I mostly do clefts, bark grafts, and chip buds. Connecting the cambial layers as perfect as possible at least on one side is very important.