(1) can be accomplished by filtering for the set of outputs in the transaction you created. I agree (2) would ideally be done to avoid issues with a copied wallet (theft or not), but I am worried about the size of the filters themselves, not just the size of the blocks downloaded after a match.

On May 17, 2018 3:43:15 PM UTC, Peter Todd <pete@petertodd.org> wrote:
On Thu, May 17, 2018 at 11:25:12AM -0400, Matt Corallo via bitcoin-dev wrote:
 BIP 158 currently includes the following in the "basic" filter: 1)
 txids, 2) output scripts, 3) input prevouts.
 
 I believe (1) could be skipped entirely - there is almost no reason why
 you'd not be able to filter for, eg, the set of output scripts in a
 transaction you know about and (2) and (3) may want to be split out -
 many wallets may wish to just find transactions paying to them, as
 transactions spending from their outputs should generally be things
 they've created.

So I think we have two cases where wallets want to find txs spending from their
outputs:

1) Waiting for a confirmation
2) Detecting theft

The former can be turned off once there are no expected unconfirmed
transactions.

As for the latter, this is probably a valuable thing for wallets to do. Modulo
reorgs, reducing the frequency that you check for stolen funds doesn't decrease
total bandwidth cost - it's one filter match per block regardless - but perhaps
the real-world bandwidth cost can be reduced by, say, waiting for a wifi
connection rather than using cellular data.