My Mom only wants to be bathed once a week. Is this common?

Whatever.

Once a week is great if she cleans up where she needs to in the interim.

Back before every house had two tubs and three showers, and water had to be heated on the wood stove, people got along just fine on a bath a week. Be glad she cooperates with that one bath/shower a week. Many don't, and that is a much worse problem.

I don't know how old your mom is, but she may be remembering how the family washed up in her childhood.

If she starts playing in the mud or becomes incontinent, you can reconsider at that time. :)

Great answer thanks. One less thing
To fight about!

I remember when Saturday night was bath night :)

Sounds OK to me... :)

Look at the big picture - if she's clean, doesn't have flaking dead skin and has no odor, and is willing to bathe weekly, accept that as a bonus. Some folks don't want to bathe even that often.

And older folks just don't need to bathe as often as they did when they were younger. Older skin dries out more than younger skin.

Timing is everything. Not long ago did I write this post and BOOM my 88 yo mom just got diarrhea and I just finished cleaning her, the commode, and the floor. And I was curious if it was'OK' that she only bathes once a week? It's all relative isn't it. .. who cares about the small stuff as long as the bigger stuff is taken care of. Still wish I had a hot Saturday night date to go to as a much needed break though... oh well. Thanks all for being there when I feel alone