I'm flying LHR to SFO in a few weeks after five months of studying abroad in London and am trying to figure out exactly what will be required when it comes to declaring items to customs, but after what's probably too much time spent googling, haven't found satisfactory answers.

I'll be bringing home things such as souvenirs for family and friends and clothes and books I've picked up here, which should all add up to less than $800.

When I list the items on the customs form, would it be sufficient to just group like items and total amounts (e.g. clothing, books, souvenirs, etc.), or do I actually need to list each individual item?
I plan to make a list of everything I've bought here and am taking back with me regardless, but it seems a little excessive to copy that list over to what could very well end up being near ten forms just to list all the little souvenirs I've picked up rather than grouping them all into one category.

I've lost track of some of my receipts (mostly from Primark and Waterstones) or simply never received one after purchasing books, clothes, etc., from outdoor markets. Could this cause any problems?

I'm probably stressing a little more than necessary, but the last time I went through customs coming home from Europe was five years ago and I was travelling with my mom, so she took care of everything, and I want to try to make sure it's as hassle-free as possible this time so I can get to my family as quickly/easily as possible.

Thanks!

Just group the items, there's not much room on the form anyway. I'm not sure if it's even necessary to list items if it's under the limit, but I usually do.

I certainly wouldn't hand over a separate itemized list unless asked.

Don't stress. If they have specific questions they'll ask, but in all my trips into the US no one seemed much interested in what I take in, along long as it's legal (and not something like fresh produce, etc).

This is not the sort of stuff customs bothers much about. Yes, group the itmes to fit in just a few lines and have the list, as mentioned, if there are questions. Which there won't be.

Customs officers want to know what you are carrying into the United States that will remain there. Personal property which has already been used won't interest them unless you plan on leaving it behind or making gifts. Don't take excluded items such as plant materials (you can find lists on the Internet.) As long as it is evident that you will be moving on in a few weeks, the guards are very unlikely to subject you to anything like an audit. Be polite and be brief.

My list when returning from Switzerland usually just says
Clothing
Souvenirs
Chocolates
Books
Miscellaneous (this one covers pretty much everything else)

I agree with others. You can group things and the customs agent will be fine with that. When the immigration agent is checking my passport for re-entry he/she might ask about my trip and what I am bringing home, why I travelled, where I travelled, etc. I sometimes wonder if the answers I give will signal a secondary scan?

Anyway, you'll be fine.

I group stuff all the time. It has never been an issue.

and if you wore the clothes you do not have to declare them!

If you are under the customs allowance, you just put the total.

You are not supposed to itemize or group items on a customs form unless you have purchased something big and duty-free (such as a computer or a Louis Vuitton suitcase).

Otherwise, just put the approximate total you've spent, know where your stuff is in case you are stopped (extremely unlikely), and move on.

I keep a running list and all the receipts in a little mesh bag. On the Customs form we just lump things together, with a total--expensive jewelry and clothing are what interests the agents. The Agricultural Inspection people are VERY thorough if you declare foods other than chocolate. Then all your luggage has to go through big scanners.

I just write "misc souveniers/gifts" and put an approximate amount in the value column. Sometimes the customs agent asks what I bought, usually not. I don't keep recipts, I don't keep a list.

I've kept the receipts ever since I bought a nice necklace in Salzburg for $100; the customs agent was convinced it had cost far more, and without the receipt...I was glad I had it.

<<The Agricultural Inspection people are VERY thorough if you declare foods other than chocolate.>>

With foods, they are mainly looking for things like fresh produce and meats. I've found that when I have had pre-packaged items—cookies, chips, crackers, cereal, jams, even liquids like "Job's tears milk" (kind of like soy milk)—and declared on my customs form that I was bringing back "food", customs agents have sometimes gotten a little miffed once they saw what it actually was and told me that there's no reason to check the "I'm bring in food" box if it's just things like that. YMMV.

I just list souvenirs. To me that covers any little things including chocolate.

I have always had them ask me about the food I bring in. Now I write what types (usually chocolates, oils, and spices), and I am still asked about it, with bags inspected a few times. Maybe I just look suspicious.

Oh gosh. I have no idea how I opened such an old thread. Sorry about the bump!

Five, six weeks isn't all that old!