trimmen
to trim
To bring something, especially hair, a beard, or a hedge, into the desired shape and shorten it by cutting.
Der Gärtner kommt zweimal im Jahr, um die Hecke zu trimmen.
The gardener comes twice a year to trim the hedge.

to trim
Loading your saved state.
to trim
To bring something, especially hair, a beard, or a hedge, into the desired shape and shorten it by cutting.
Der Gärtner kommt zweimal im Jahr, um die Hecke zu trimmen.
The gardener comes twice a year to trim the hedge.

You can recognize the meaning of 'trimmen' (to trim) from the sentence structure: 'sich trimmen' means to keep oneself fit. 'Etwas auf etwas trimmen' means to orient something toward a goal. Without these additions, it is usually about cutting hair or plants.
Er trimmt sich jeden Tag mit Joggen und Krafttraining.
He gets fit every day with jogging and strength training.
In the meaning of 'kürzen' (to shorten), 'trimmen' (to trim) is typically used for things that grow. Common combinations are: 'den Bart trimmen' (to trim the beard), 'die Haare trimmen' (to trim the hair), or 'die Hecke trimmen' (to trim the hedge).
Kannst du mir die Spitzen meiner Haare ein wenig trimmen?
Can you trim the ends of my hair a little?
When it is about physical fitness, 'trimmen' (to get fit) is always used reflexively: 'sich trimmen' (to get oneself fit). The reflexive pronoun is a fixed part of the expression here.
Viele Leute trimmen sich im Fitnessstudio.
Many people get fit at the gym.
To express that someone or something is being oriented toward a goal, you use the fixed construction 'jemanden/etwas auf etwas (Akkusativ) trimmen' (to gear someone/something toward something).
Der neue Mitarbeiter wurde von Anfang an auf Leistung getrimmt.
The new employee was geared toward performance from the beginning.
The meaning of 'justieren' (to adjust) is specialist language. It is used almost exclusively in sailing (sails), aviation (aircraft), or technical contexts.
Der Pilot muss das Flugzeug für den Landeanflug trimmen.
The pilot has to trim the aircraft for the landing approach.
to hire / adjust / stop
'einstellen' and 'trimmen' can both mean changing something technically so that it works better. 'einstellen' is the more general word here. For example, you can set or adjust a heating system, a camera, or a machine. 'trimmen' is more specific and is used in technology or sailing when something is finely adjusted for good performance, balance, or the right position. The words can be confused because both refer to a kind of adjustment. In everyday language, 'einstellen' usually sounds more natural. 'trimmen' fits better with sailing, boats, aircraft, or similar technical situations.

Bei starkem Wind trimmt der Segler das Segel neu.
In strong wind, the sailor trims the sail again.
Vor dem Foto stellt Lisa die Kamera auf Nachtmodus ein.
Before the photo, Lisa sets the camera to night mode.