How to distinguish watch-only addresses from spendable addresses when deleting addresses An answer to I have watched addresses in my wallet..how do i use them? says:

&quot;If you do not have the private keys for those addresses, then they are not yours and you cannot do anything with them. Those addresses and their associated Bitcoin do not belong to you, so you cannot use them.
You can delete the watch only addresses if possible; you will not lose any money if you delete just those addresses because there is no money that belongs to you in the first place with those addresses. However be careful of deleting the wallet entirely, it could have addresses and private keys which do belong to you and those you do not want to delete.&quot;

Based on the answer above, how do you then establish which addresses belongs to me that I must not delete?
It depends on which wallet you are using, if you are using the Bitcoin core wallet for example, you can see the amounts separated, the watch-only amount will be one, and the spendable amount will be another one.
You can also use the command listunspent into your console to know which addresses contain the spendable amounts.