In the UK, a 'laundrette' is either a coin operated facility where the public may just walk in and use the washing machines and driers, or, it may be an attended facility where people hand in their laundry for cleaning and collection later.
All three words have the same meaning, but I think you will see the first two more frequently in the UK and in countries influenced by British English, and the last one in the USA and countries influenced by American English. For many years in the 20th century, the word "Laudromat" was a trademarked name by an American company, Westinghouse, which could mean either ONE of its machines or a store that had coin-operated machines. In 1993, Westinghouse allowed its trademark on the word to expire, and now it only seems to mean a store with washing machines and dryers.
I'm going down the river to wash my clothes (metaphorically)
"The launderette." - The shop where you can take your clothes to be washed. Normally with coins but I have seen a few where you pay the staff who work there. As in "I've gotta go to the launderette soon, I've go a pile of washing to do".
"I'm going down the river to wash my clothes"- (metaphor) As in going back to the olden days when people used to wash in the river. Just tells the person you're going to wash your clothes but adds a bit of a joke to it. "I'm going down the river to wash my clothes"
"The launderette." - 衣類を持って洗濯に行く店のことです。普通はコインですが、そこで働くスタッフにお金を払う所もいくつか見たことがあります。
例：
"I've gotta go to the launderette soon, I've go a pile of washing to do".
〔訳〕そろそろコインランドリーに行ってこないと。洗濯が山のようにある。
"I'm going down the river to wash my clothes"-（メタファー）昔、川で洗濯していた時代のように。洗濯に行くことを冗談交じりで伝えます。
"I'm going down the river to wash my clothes"
〔訳〕川に洗濯に行く。
itoさん
ご質問どうもありがとうございます。
様々な表現があると思いますが、いくつ自然な表現を紹介します。
I'm planning on staying abroad for a longer period of time, so I'm thinking of using laundromats.
I'm planning on staying abroad for a longer period of time, so I'm playing with the idea of using a laundromat.
--- thinking of doing ___ = ～を考えている
--- to play with the idea of ___ = ＝～しようかな、と思っている（まだ決定的決めていないですが）
お好みに合わせて使い分けてみてください。
ご参考にしていただければ幸いです。
Either of these terms can be used to describe the place. It is a place with a lot of washing machines and you pay as you go to use them and do your washing.
「コインランドリー」はlaunderetteと言います(*^_^*)
例）
I'll go to the launderette.
「コインランドリーに行ってきます」
launderetteはイギリス英語でよく使われますが、アメリカ英語では、laundromatと言うことが多いです(*^_^*)
以上です。
少しでも参考になれば幸いです(*^_^*)
The basic word for a place where you can wash and dry your clothes is called a Laundromat.
Adding the words, "coin-op," describes the concept that the laundromat works with quarters or types of coins to pay and operate the machines.
"self-service," can describe that the laundromat is done by oneself and there is not a worker who washes the clothes for you.
イギリス 
アメリカ合衆国 
日本 
ドイツ 
