If I have lost money on a stock, but I want to keep it long term, is there any reason not to sell and buy back for tax (loss) purposes?

Easy hypothetical (that is not so hypothetical) - I recently invested $10,000 dollars into stock A. The economy just took a dip and that stock has dropped 30 percent. I want to keep an investment in this company long term, but I am also wondering if it would be advantageous to sell at a loss and buy back immediately (keeping the same number of shares) for tax purposes. I would not anticipate moving/selling these shares again this year.

Would doing this be a net positive because I would be able to count it as a loss for next tax season? Or am I missing something?