postgresql delete old recorde

Hi,
I'm using traccar server with PostgreSQL database ,
i would like to remove old data .
can anyone help?

I use pgAdmin and Query editor to delete records of tc_events and tc_positions

SELECT * FROM public.tc_events
WHERE servertime > '2022-01-16 00:00:00'
ORDER BY id ASC LIMIT 10

DELETE FROM public.tc_events
WHERE id < [nuerical position id]

SELECT * FROM public.tc_positions
WHERE servertime > '2021-12-23 00:00:00'
ORDER BY id ASC LIMIT 10

DELETE FROM public.tc_positions
WHERE id < [nuerical position id]

Hey ,
when i delete some rows in the position table the size didn't change

It won't change. That's how databases work.

so if the size does not decrease
Why would we delete the old data ?

Because existing space in the database will be reused by new records and it won't grow.

that make sense . so we don't have to shrink it cause it will grow again.
Thanks

is it okay that the size of tc_positions more than 20GB ?

To recover space used in postgres I use:
VACUUM: Free up space for reuse.
VACUUM FULL : Frees up unused disk space.