For a trip that last longer the amount of clothing you are willing to take, you will need to consider how you are going to deal with doing your laundry.
I hate having to deal with laundry on a trip, so I tend to take more clothes so I can go longer without dealing with the task. It is such a nice feeling after the laundry is done though, as it means I don't have to think about it for a while. On the other scale, you can pack light and even do some nightly washes, taking advantage of quick drying materials.
If you plan on getting someone to do it all for you, then you do not need to think much further, although you will need to find an acceptable place to do your laundry. This can save you time and reduce the items you will need to take.
Doing your own laundry can be for modesty reasons, to save money, reduce the chances of harm to your clothes, or them being lost etc.
Here are some tips and items you might need if you are performing laundry related tasks on your trip:
Portable Ironing Board
You can get quite small ironing boards to make your ironing duties easier.
If you need your clothes wrinkle free and have the room to spare. There are some portable irons as well.
There are different types, like rollers, or battery operated machines, but they help remove that lint that is not meant to be on your clothes.
A special bag you put into the washing machine with delicate items like lingerie, shirts etc. Often made of a mesh material that reduces the chance of items being damaged.
A compact and stretchy clothesline that can attach (often loops or hooks) between items to create hanging space for items you want to dry (often inside a room).
Laundry without detergent is just wetting your clothes. Single use packets can be useful for travel.
Normally used during the rinse cycle in a washing machine. Optional, but its job is to make fibres "stand up" given the material a softer feeling.
For when normal washing detergent is not getting the job done, apply this to a stain for extra cleaning power.
Can be used to store dirty laundry in your bag and transport your clothes to and from where they will be cleaned.