I have adopted my ex neighbours cat. My neighbour moved out about 18 months ago, however after having a baby she was stressed out about baby and cat. I have now taken her in, the reintroduction to my cats has gone quite smoothly as they know each other. But when do I start letting her out again? She does know the area.

Hi and welcome!
You dont say how long you have adopted this cat for, so I personally would wait 5-6 weeks min. so he/she can fully understand that this is their home and need to get used to you as their slave and to trust you. If you let the cat out too soon it could go straight back to your old neighbours house and hang around there and possible upset your new neighbour if they are not cat lovers.

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Black with white around his private area



Black Tortoiseshell




R.I.P Patch my well behaved boy dog
R.I.P. Abby and Rebel my beautifull litter sister cats

I agree with the above, keep her in for the full recommended time because she still has to learn which is her new home and bond with you enough to return back to you rather than her old haunts.