We use different service kits depending on the type of ride, the amount of time we'll be out, how many people - if any - that we're riding with, and the time of year.

Check out Overland's toolkit recommendation for all-day mixed-terrain riding here. Overland's road kit and mixed terrain kits are similar but different. Don't make the mistake of bringing one for the other.

An all day road ride is quite different from a typical club ride. Don't make the mistake of grabbing your road ride saddle bag; a spare tube and one quick-fill won't do the job on a 12-hour back-road ride.

Here's our ideal pack for:

Duration of ride: 6-20 hours
Ride Terrain Type: Pure pavé
Location: Exurban to rural
Time of Year: Mid-spring to late fall
Co-Riders: Zero or more

Here's what we carry for a typical all day paved ride. Our ideal kit for this type of ride includes a saddle bag - and jersey pockets - with five categories of equipment: Safety, repairs, nutrition, weather management, and being a good co-rider.

Safety & Emergencies

Identification
Phone
Emergency contact information or Road I.D. bracelet
Accident Report card - When you're 10-hours into a ride, a bit hazy and tired, it's great to have a way to ensure you collect all pertinent information if you have an interaction with a car.
Cash - If you're bonking, a 10 dollar bill is a wonderful thing.
Credit card
Chamois creme - single serving

Repairs

Spare tube or two: New tubes - not tubes that have been in your repair kit for a season; these will have holes worn in them. Also, make sure the tubes are the right size for your tires.
CO2 cartridge or two
CO2 inflator head. Here's our favorite CO2 inflator, by far.
Mini pump that fits in your jersey pocket.
Tire lever x2
Patch kit
Multi-Tool that includes at least a dozen tools - or the equivalent of this in some form. There are a lot of good choices; here's what we use. Recently it's become important to have a Torx wrench with you; unfortunately these are becoming fairly common. A T25 wrench is really important; a T35 is less common but some high end parts are beginning to use this size.
Chain tool - that works with your chain type: 11-speed, 10-speed, etc. A good multi-tool will include a chain tool.
Spare chain pin or Powerlock
Duct tape - fixes just about anything.
Tire boot - a dollar bill also works here, but money's for spending, tire boots are for tears.

Weather Management: Depending on the season this could be a number of items:

Wind jacket, vest, rain jacket, knee warmers, balaclava, etc. Not a lot worse than being cold when you're tired and bonking.

Nutrition

Food bar or two: If you're starting to bonk eating a food bar will get you to a real store to get real food.
Bloks or shots for quick energy if you're starting to bonk in the last hour of the ride.

Being a Good Co-Rider

Sun screen
GPS device with the route pre-loaded.
External power supply that will keep your GPS unit charged for 12+ hours of ride time. Most GPS units won't really last for 12 honest hours. Having your GPS die 2-hours from home base is miserable. Don't risk it; bring a spare battery.
Charging cable for the spare battery to the GPS unit.
Brave Soldier Crash Pak
Tampons

For the Very Prepared

If you definitely don't want to end your ride early due to a mechanical, electronics failure, or bonking, here's an exhaustive list of gear:

Leatherman with tools not included in a multi-tool.
Cat's Tongue towel - Great for cleaning up after a repair.
Replacement spokes or Fiberfix
Will you need lights? Taillight and head light, too? Even if you're sure you'll be back before sunset we still ride with lights; we can't tell you how many times we've rolled home well after dark even when we were 100% certain we'd be home before dusk.
Backup battery supply for phone, light, etc. This could be the spare battery for your GPS unit, too.
Charging cable for phone, lights, etc. Make sure the cables have the correct ends.
Camera

All of this will fit in your jersey pockets and a large-ish saddle bag; there are many on the market. Overland's preference from trying many options is the Revelate Viscacha bag.

Here's other posts that you might find useful for the long ride.