The database layout should not change when you add more data to it, so the user data should definitely be in one table.
Also:
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Having multiple tables means that you have to create queries dynamically.
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The cached query plan for one table won’t be used for any other of the tables.
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Having a lot of data in one table doesn’t affect performance much, but having a lot of tables does.
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If you want to add an index to the table to make queries faster, it’s a lot easier to do on a single table.