There are hundreds if not thousands of research articles and blogs available online that tout the necessity of having established, daily routines for young children. The Center on the Developing Child at Harvard University explains how creating steady, daily routines for a child can assist in normal brain development. Along with having supportive family relationships, a child needs to participate in structured routines in order to develop what is called executive function, which the Center defines as “skills [that] are the mental processes that enable us to plan, focus attention, remember instructions, and juggle multiple tasks successfully” (https://developingchild.harvard.edu/science/key-concepts/executive-function/). Developing a child’s executive function early on and in a healthy manner sets them up nicely for things they have to do later in life such as attend school, hold jobs, create friendships or relationships, run a household, etc.

Some children thrive off of overly, predictable routines in their schedule, including those on the autism spectrum. Behavioral problems seem to decrease when these children know exactly what’s going to happen next going from the transition to transition. However, predictable routines are not necessary for many children to develop in a healthy manner. In fact, routines that are completely foreseeable come with some negative consequences for both children and parents:

Parents and other family members just might go crazy: Stringent routines impact everything about the day for everyone in the house: bed-times, TV shows, food preferences, outdoor play, chores schedule, school, homework, sports, lessons, etc. The child may be the one participating in these tasks, but the parent has to be around to enforce the schedule. There is nothing wrong with having a plan. On the other hand, a routine can be too rigorous to the point where the child will not know how to react if something in the day gets canceled or switched.
Children will lack development in flexibility: Unexpected changes in the schedule should be expected. Sometimes the electricity goes out, and your child will not be watching their favorite morning shows before school. Sometimes, mommy can’t get to the grocery store on time to get all of the child’s favorite foods at the beginning of the week. Sometimes, bedtime will be late because the family is out and about doing other activities at night. A child needs to be exposed to opportunities that make them flexible in the event that unexpected things happen. Flexibility means a much easier time coping with the changes instead of melting down the moment something goes awry.
Activities outside of the house are limited or greatly disrupted: Having a tight home-based routine means makes out-of-the-house activities more complicated. The child now expects routines to specifically impose on community activities to make them more comfortable: bringing favorite toys, bringing favorite snacks, knowing EXACTLY where they are going and what they are doing before going, and making sure that the parent does everything in their power to make sure that activity isn’t unexpectedly canceled.
Children lack the ability to learn or to try anything new: A predictable routine that incorporates all of the child’s preferences that make them happy might create barriers for new learning and exploration: trying new foods, watching new movies, wearing different clothes, playing with new friends, etc.

Make-shifting a flexible routine for your child doesn’t have to be hard. Of course, having structure is very healthy but there is always room to change it up for the sake of your child’s development:

Expose your child to choices: Save yourself some near-future problems and have Plan B on the back-burner. If an activity, a favorite toy, a favorite food, or a favorite anything falls through fill your arsenal with some additional choices that your child could still enjoy.
Give them some warning: Your child is young, but not dumb. No matter how young, you can start giving them some verbal warnings like “Honey, it might rain today. If it does rain, we might not get to go to the park”. Verbal warnings early give a child a chance to develop their language skills anyway.
Handle behavioral reactions one at a time: You will never be able to please your child 100% and tantrums are inevitable. Your child will tolerate some changes and hate others. Handle those tantrums accordingly and one at a time.
Provide opportunities for new learning: Be willing to introduce new activities, new toys, or new foods to your child on a regular basis. Foreign opportunities enhance their flexibility and ability to learn, despite whatever reservations or discomforts they may have to begin with.