Let's refine what we mean here. Of the five basic adverb types, Manner, Time, Place, Frequency, and Degree, we are most concerned with Adverbs of Manner. These explain, tell us, the way something is done. "He wrote lazily." We are less concerned with the others. Your homework is to look them up and work out when, where, and whether to use them, but only after reading the rest of this segment. Some of them you may not even recognise as adverbs.
We are taught about adverbs, adverbial phrases, and adverbial clauses in school. We use them when we talk to other people. They have validity in describing how to mix chemical A with chemical B. We do it 'slowly', or 'carefully', or 'too fast'. They are great things for telling us things. They are not wonderful for showing us things.
Even the word to describe us is incorrect. We are not 'Story Tellers', but are writers who show people the worlds we create.
Which is more effective? Is it to get you to develop a picture in your mind with the words a good author writes, or for them to tell you what is going on?
Adverbs have a use, but not to paint pictures. Which paints the better picture?
It's harder not to use adverbs. They're a great shorthand, a laziness, and one that leaves the reader told, not shown. And yet they have a place.
In dialogue, in the actual words said, use them precisely as you do when you talk. Outside the words spoken, use them not at all, not even to describe the way the words are spoken. So there can be no "I need time to think," Bert said slowly.
What would you use instead?
If Bert needs time to think his speech pace will reflect this. The adverb adds nothing to the text. Lose it. But, if you want it, use a description. Use more words. Try something like: Bert was pensive. "I need time to think." or maybe reverse it: "I need time to think." Bert was pensive.
Try it for yourself. Don't take my word for it. Look for adverbs in your and other people's descriptive prose, and see how they can be improved.