You should always carry a spare valve or bag with you in a bag. Make sure you have enough to cover the time you will be away. Take a change of catheter kit along with you as well if traveling away for a long time.
If you are flying, you should keep your spares and accessories in your carry-on luggage, as other bags can be easily lost or delayed in transit. You may wish to choose an aisle seat when booking so you can get to the toilets easier while in the air.
If you need bed protection, then you should check that a mattress protector will be supplied where you are staying. If not, then ask for the mattress size before travel and take one with you. If in doubt, take a large cover or sheet.
Take some small plastic waste bags or bin liners.
If washing facilitates such as showers and baths are available, check when they are open.
In case you have an accident, you might want to take some pegs and a small clothesline and/or folding coat hanger could be useful to take with you. There is usually a charge for doing your own laundry.
In places with hot weather, you will need to drink a lot more water than usual. Otherwise, you will become easily dehydrated and your urine becomes dark and concentrated – which may irritate your bladder.
In cold temperatures, more urine is produced and you may need to go to the toilet more often. Be prepared for this.
Changing what you eat and drink can also lead to constipation or diarrhea. You should be careful what you choose to eat. You may also want to buy bottled water to drink instead of from a tap.