I have 15 investment accounts (6 education, 5 taxable, 4 retirement) with over $1M in paper assets. All DRIP except one taxable account. When I early retire, I will turn off the DRIP on the taxable accounts and live off those. If I need it later, I will turn off the DRIP on the retirement accounts. SRIP allows me to buy ~$40,000 a year with no commissions.
As far as tracking basis, I have 5 accounts where it might matter, but I do so for all 15 accounts. Entering purchases in a computer program takes about 10 minutes a month. Of course, if you hold the assets until death and just live off of the dividends, then there is no capital gain tax.