select.vue

<template>
  <div>
    <select v-model="select" @change="changeSelect">
      <option value="1">Um</option>
      <option value="2">Dois</option>
    </select>
    <div>Selected: {{select}}</div>
  </div>
</template>

<script>
  import {debounce} from 'lodash'
  export default {
    data() {
      return {
        select: ''  
      }
    },
    methods: {
      changeSelect: debounce(function() {
        console.log('Changed!')
      }, 1000)
    }
  }
</script>