I practice every day. If I don’t practice for one day, I know it. If I don’t practice for two days, the critics know it. If I don’t practice for three days, the audience knows it.” Vladimir Horowitz, pianist.
I’m currently writing “Hi, I’m Here for a Recording, the ordinary life of a voiceover artist,” so I’m reading a bit about writing (it’s my favourite form of guilt-free procrastination). I came across the quote above in the book How to be a Writer: Building Your Creative Skills Through Practice and Play 
When you first start to create theatre, it’s difficult. You might not be great at improvising, you might be used to feeding off a script to create a character, you might not enjoy creating material when you don’t know whether it’s going to be used in the final piece or not.
Devising theatre (and indeed creating any kind of theatre) is a process. You try things out; you ditch them. You play games, you take part in exercises, you explore characters and scenes not knowing where they’re going to take you. Unless you do this over and over again, you will never learn, you will never grow as a performer and person and you will never master the craft.
Acting, like all types of art, needs both talent and craft. On my first day at drama school one of my tutors told us, “You need to work hard at perfecting your technique. Talent will come and go, but your technique will keep you working.” He was so right. Technique, rehearsal and practice will make you Good. Then when you are inspired, when you have good days (or even good long periods), you will be Excellent. But talent without technique doesn’t last.
So, when you’re bored of repeating that scene again and again and again, remember Horowitz words above and learn from every single moment as you practice your craft.
Your Handy Companion to Devising and Physical Theatre 