I have had to adopt very strict habits for my phone, keys and wallet; where I keep them (specific pockets in nearly everything I wear with a few necessary exceptions) and how often I check for them (basically made this become a nervous habit). Whenever something is out of my wallet - credit card, ID, insurance card, etc - I keep my wallet in my hand until I get whatever I took out back and put it away. I always immediately put appointments in calendar and have multiple reminders turned on by default. I am not this detail oriented or **** by nature; it was very difficult to get these habits established, but the consequences of my absent mindedness were occurring far too frequently. I didn't establish the habits until a few years ago as it was/is getting worse. Most of my life I lost stuff and missed appointments all the time.