My current gulpfile with watch inside

gulpfile.js

var gulp = require("gulp")
var server = require("./tasks/server")

gulp.task("clean", require("./tasks/clean"))

// generated assets
gulp.task("icons", require("./tasks/icons"))
gulp.task("scripts:linting", require("./tasks/scripts-linting"))
gulp.task("scripts", ["scripts:linting"], require("./tasks/scripts"))
gulp.task("styles", require("./tasks/styles"))
gulp.task("styles:all", ["icons"], require("./tasks/styles"))

// html & static
gulp.task("html", ["styles:all", "scripts"], require("./tasks/html"))
gulp.task("static", require("./tasks/static"))

// build
gulp.task("dist", [
  "clean",
  "scripts",
  "icons",
  "styles:all",
  "static",
  "html"
])

// dev tasks
gulp.task("server", ["dist"], server.start)
gulp.task("default", ["dist", "server", "watch"])
gulp.task("test", ["dist"])

gulp.task("watch", ["dist"], function() {
  gulp.watch("./src/**/*.jade", ["html"])
  gulp.watch("./src/static/**/*", ["static"])

  gulp.watch("./src/**/*.css", ["styles"])
  gulp.watch("./src/icons/**/*", ["styles:all"])

  gulp.watch("./tasks/**/*.js", ["scripts:linting"])
  gulp.watch("./tests/**/*.js", ["scripts:linting"])

  gulp.watch("./dist/**/*").on("change", server.livereload)
})