I find it everytime. Yup, I see those bags that you forgot about. You didn't have time to get them out or you stuck them in the closet and forgot about them. Oh, did we just waste 30 minutes going through bags you forgot to donate?
Don't make donating items another project! Get them out! The sooner you free yourself of these excess items, the better you will feel. Yes, I leave homes on a daily basis with a carload of stuff. One time people stared at me the whole way back to the city from Highland Park. What's wrong? Have you never seen a chick driving around with a life size stuffed bear in the passenger seat?
Here is a comprehensive list from Miss Minimalist that will help guide you in donating items.
When you know that you are going to do a purge, it's important to have the proper items on hand to pack up your donations. I like the force flex bags. They tend to hold more items and don't break as easy. Don't get those dollar store specials. Avoid using the contractor bags. They will get too heavy to carry and some of them have an oil that will stain the carpet.Also have some small boxes and packing paper or newspaper for fragile items.
If you are lucky enough to live in a space where Amvets or The Epilepsy Foundation picks up, get on their schedule. Plan to purge right before that time and stage in the front of your home or garage. I have heard that Amvets has a limit of 22 bags per pick up. If you have excess- use your neighbors porch(have no shame. For general donations, you can drop items off at the Goodwill Or Salvation Army. Some of them will unload your car for you!
For Computer related items, locate your town's electronic recycling center. Some towns have a center, others have a twice yearly pick up. In Chicago, we are lucky to have the Goose Island Recycle Center. Aren't they lucky to see me every week. I know their schedule by heart.
If you have donations that are slated for friends or family, make sure you drop them off within a week. Or for smaller items, put them in the mail. Don't let them sit. Ask your friends and family if they want the items before you show up with them.
Keep it simple! Just let it go!