Jordan, in Spanish you NEED to conjugate ALL verbs so the listener understand all what you want communicate.
You can say:
- Yo viajarè a Londres el próximo otoño, you can omit the subject (Yo) and say: "Viajaré a Londres el próximo otoño" and the listener will understand both phrases because the verb conjugated has informed that the subject is the first person of singular and future tense.
No matter how long is the text, no matter if the subject is the same or not, but you need to conjugate allways the verb.