We all remember pulling a fast one in an attempt to get a day off school - meaning it's tricky as parents to know how ill our little ones really are.
You don't want to keep them off school if it's not needed, but equally you don't want to be the parent who sends a sick child into a classroom full of kids.
To give us a helping hand, the NHS has issued guidance over the illnesses children are likely to get, and the best way to deal with them, as reported by Nottinghamshire Live.
For many it's fine to head to class and for others a duvet day is the best solution.
Here's what the NHS says:
When it's fine to go to school
Cold sores
Just make sure you let the teacher know your little one has an infection that could be passed on.
Advise them not to touch the affected area or kiss anyone while they have a cold sore, and also to avoid things like sharing drinking cups and towels.
Conjunctivitis
Children are fine to go to school with the eye condition caused by infection or allergies.
You should get advice from a pharmacist over the best way to treat it, and children should be told not to rub their eyes and to wash their hands regularly.
Coughs and colds
Minor coughs and colds won't cause huge issues, but they should be kept off school with a fever until the symptoms pass.
Tissues should be thrown away to help prevent the spread of germs and hands should be washed regularly.
Hand, foot and mouth disease
The common illness includes symptoms of a sore throat, mouth ulcers and a rash. It shouldn't be confused with foot and mouth disease, which affects farm animals.
If your child seems well enough to head into school, there's no need to keep them off. Similar to a cold, tissues should be disposed of and hands should be washed regularly.
Head lice and nits
The NHS advises that children are fine to go in with head lice, but parents should let their teacher know if their child has them.
Slapped cheek syndrome
Once the rash of slapped cheek syndrome has appeared, children are no longer infectious so it's fine to let them mix with other pupils.
If you suspect they may have it, take them to the GP and inform the school if they are diagnosed.
Sore throat
It's fine to attend school with a sore throat, but if they are showing signs of a fever, keep them at home until symptoms pass.
Threadworms
The illness results in small white worms appearing in your child's faeces or around their bottom. Children are fine to attend school but parents should seek advice from a pharmacist, who will be able to recommend a suitable treatment.
When they shouldn't go to school
Chickenpox
They should be off school until the spots have crusted over, which usually happens about five days after they first appear.
Diarrhoea
Keep them away from other children while they are ill, and also for a further two days after the symptoms have passed.
Ear infection
With severe earache or symptoms of a fever, it's best to keep them away until they are feeling better.
Fever
Wait until they are feeling better to allow them to return.
Impetigo
Impetigo is a contagious skin infection which requires antibiotic treatment from a GP.
Children should be kept away until all the sores have crusted over and healed, or 48 hours after they begin their course of antibiotics.
Once they return, they should keep their hands clean and not share things like towels or cups with other students.
Vomiting
Your little ones shouldn't return to school until two days after the symptoms have gone.
When it's fine to go to school - but only once treatment has started
Ringworm
The common fungal infection has nothing to do with actual worms. If your child has ringworm see a pharmacist, unless the markings appear on their scalp, in which case it's best to see a GP.
Children are fine to go to school once they have started treatment.
Scarlet fever
They'll need antibiotics from the GP to banish the symptoms, otherwise they'll be infectious for two to three weeks.
They can attend school 24 hours after starting the medication.
For any illnesses, it's also worth checking with your school as their own guidelines may vary.
