we have a 5 year old rescue cat. only had him for 3 months. about 2 months ago we started to let him go outside but he was still using the litter tray up until 10 days ago. since the nada (great actually) but I wonder if this is something to worry about. he is frequently outside during the day for up to 2h but spends a good 10h at home from evening till 7 am when I let him out. he doesn't use the litter at all during this time. no accidents though .
he appears very will in himself. no concerns at all.