Every family raising bilingual children needs to have, at the very least, one family language plan. Ideally, they should start the planning process at the same time as they start all the other planning for baby preparations – during pregnancy.
A family language plan is a longitudinal plan that follows a child from birth (or later) through to the end of secondary school, to give the parents and child the best chance for success. The process of creating a family language plan helps parents consider their options, prioritize, and take the necessary steps to reach their goals. This includes goal-setting, mapping out where the input in each language will come from (in terms of people and time), how literacy will be approached in each language and how challenges will be dealt with. One plan is fine for families who are living permanently in one location. Families who move, or who may move, need to have alternate plans, each one designed for a certain set of circumstances. For example, a family who are living in the Netherlands, and speak German and Chinese, will have an initial plan that is based on the childcare/schooling opportunities available to them if they stay in the Netherlands. If there is a possibility of the family moving to an English-speaking country, they must have an alternate plan which outlines how they will adjust to continue to meet the goals of German/Chinese bilingualism, and how they will deal with Dutch, if it was a part of their plan. If there is a possibility of the family moving to Germany, they will also have an alternate plan that outlines their bilingual strategy for the target languages of German/Chinese, and any others that were part of their original plan, such as Dutch or English. As you can see, the more languages and life possibilities the family are dealing with, the more complex the planning process becomes! Although many families don’t formally write down the whole plan and alternate plans, the process of family language planning helps families understand the key elements for bilingual success, the the process of resourcing a plan, so that they can make changes as their needs and situation change.
The benefits to this type of planning are numerous, and include ensuring quality language input in a variety of situations, and also include elements such as support for literacy and additional languages. By anticipating the language needs of the children across different life circumstances, the parents have a better chance of guiding their children towards full and functional bilingualism.
on raising bilingual children 
That makes sense, though it could be challenging to have a detailed plan many years in advance. We don’t have plans for school yet but we pretty much figured out that we’ll have to give the non-dominant language a “boost,” depending on where we’re living.
Absolutely – we usually work on big picture goals for the long-term plan and the details for the immediate future – by doing the detailed planning for a family situation right now, they learn how to plan in general, so can tweak the plan as life and circumstances change!