Every workshop has the same story about its vacuum: it was great when new, lost its bite within a year, and ended up living in a corner. Almost every time, the motor and the impeller are perfectly fine, and the suction loss is the filter, the bag, or both. Vacuum bags, filters and parts sit alongside carbon brushes as the most-bought consumables on the site, and for good reason.
The pattern is consistent. A vacuum that runs normally but has lost suction has a clogged filter — you can usually see fine dust caked into the pleats once you take it out. A vacuum that runs hotter than it used to, or trips the motor protection, has a filter that has gone past clogged into completely blocked, with the motor working against a sealed system. A vacuum that smells of burning plastic on a long run has been doing that for a while and needs the filter changed yesterday.
HEPA and class-M filters lose efficiency long before they look dirty. The pleats can fill with the very fine dust that the filter is designed to capture, which then prevents air passing through. The standard advice on a workshop extractor used for plaster or MDF is to change the main filter every six months of regular use, more often on heavy plaster work. Bags should be changed when half full — a full bag is actively blocking airflow.
If a fresh filter doesn't fix it, check the hose and the inlet. Long hoses on workshop extractors collect a surprising amount of debris in the bends. A blocked hose mimics a failed filter exactly, and is the most common false alarm we see.
If the motor itself is the problem — a vacuum that no longer starts, or starts then trips out — brushes are the next thing to check. Brushed vacuum motors wear the same way drills do; see carbon brushes for appliances for the appliance fitments. For the full range of replacement consumables and parts, the tool parts hub is the fastest route.