Miele Guard S1 bags and filters
TU dust bags, an SF-HA 50 HEPA filter and an SF-AA 50 exhaust filter. Any of the versions below will do.
The same parts fit every version in the "Also covers" list, so check your plate against it before you order.
Dust bags
HEPA filters
Exhaust filters
Finding the model number
Check the plate before you buy anything: a Miele name on the box can cover more than one version. Data plate is underneath the vacuum cleaner.
When to change them
Change the bag when the marker in the bag change indicator turns red (fine dust can trigger it early; hair and fluff can fill the bag before it shows). Each 4-bag pack includes a fresh AirClean exhaust filter; Miele says the exhaust filter needs changing about once a year on average. (source)
Don't judge a bag by how full it looks. Fine dust clogs the paper or fleece long before it's packed, and suction drops off with it. Trust the indicator over your eyes.
If the indicator says full with a nearly empty bag, look for a blockage in the hose or floorhead before you swap it.
Only rinse a filter the maker says is washable, and let it dry right through before it goes back in. Most of the "it smells" complaints start with a damp filter.
Quick answers
Which dust bags fit the Miele Guard S1?
TU, which Miele sells in 2 different packs.
If I've got a Miele Guard S1, which HEPA filter do I need?
SF-HA 50, or any of the other 2 Miele versions listed above.
What exhaust filters does the Miele Guard S1 take?
SF-AA 50, or any of the other 3 Miele versions listed above.