Multiple update logic problem

I have a little question here. It is about multiple update.

For the first time, I multiple insert some records to a table and the next time, if I want to make changes (let's say insert more records), I will have redundant records isn't? So, how do I solve this problem. Insert first, then delete the redundant records. Is it possible to only insert records which is not redundant?

Eg, (I use checkbox style in a form to add records. The process page I use insert into [table] (field)values() style)
HobbiesID, Hobbies, UserID, Status
1, basketball, ,steve, yes
2, bowling, steve, yes

The next time, I come back again, the form will have both basketball and bowling's checkbox checked. If, I add select another checkbox for badminton, how the process page code look like?

Hope everyone understand my scenario here. Thanks for all feedback.

Basically you are going to have to do a search through the recordset before inserting the data. If the search returns no records then update it.