Most septic tanks need to be pumped every 5 to 7 years including the 1,000 gallon septic tanks depending on how much use the septic tank gets.
The more often you fill the 1,000 gallon septic tank the more often it will need to be pumped.
To help keep the waste broken down in your septic tank I would recommend using some RIDX every year which helps to break down the solid waste so that the septic tank doesn't fill up as often.
But having the 1,000 gallon septic tank pumped every 5 to 7 years should be good enough to keep the septic tank from backing up into your house.
I always had my septic tank pumped every 5 years just to make sure it never backed up and it only costed me around $80.00 each time I had the septic tank pumped which was a very good deal.