If you don't plan for recovery you can easily forget to take it and over-cook your training. This puts you at risk of over-training and injury. Here are some ways I like to plan recovery with athletes.
Given that we can't go hard every day it's important to have regular easy days to recover from the hard sessions.
I usually plan easy days on Mondays, after the hard weekend block of training and Fridays to prepare for the weekend block of training. So a typical week might look like this:
This splits the week nicely into two blocks - Tuesday to Thursday and Saturday to Sunday allowing you some volume and time to recover between harder workouts.
After 2-4 weeks like those above you will have made some fitness gains but you will be starting to feel tired. In order to allow your body to adapt fully to the stimulus of the last few weeks you will need to have a few easy days.
I usually create a 'de-load' week/period in which you have a few easy days. This might include more complete rest days, very light training and, for those who can handle it a small amount of speed, but overall the volume and intensity is much reduced in this cycle.
Typically it might look like this:
After the five days of easy training many people are fresh and ready to do something a bit harder, so they might like to try a practice event or a short time trial to update their training zones.
For women it can be useful to combine training blocks with their monthly period having the easy/recovery weeks in line with the worst days of their menstrual cycle (often days 25 to 28 on a 28 day cycle). You can check out my article about this here.
How frequently you need an easy week is individual; some people need one more frequently than others, so don't be afraid to experiment and find what works for you. At least one easy week each month is a good idea.
Easy means 'easy for you' so a good rule of thumb would be over a week to aim for around 50% of your usual weekly volume and stick to a very small percentage of that as higher intensity.
You should start to feel ready to train after 3-5 days, so if you are still feeling tired after that time, you may need more rest and/or you may not be taking it easy enough.
Some athletes do not work well with complete rest while others perform much better off complete rest days.
An easy day can be a complete rest day or just very light (cross)training (swimming, walking, pilates, yoga, stretching).
Either way, it is a good idea to have some complete days off, it helps reset you psychologically as well as helping your body recover.
Remember, the consequences of under-recovering and over-training can be devastating, too much rest is better than too little.