This varies very much as you said, by model. And also as the model changes how she does things.. years ago the amount of offline contact I did was much greater because I had a different way of doing things.
Bottom line: It's going to be VERY much based on level of spending.
One thing that drives me bonkers is when someone tips very highly for a short period of time - lets say drops 10k.. and then stops tipping well. Then expects me to continue our HIGH level of interaction for years and years. I think you should also consider how much other people spend on the model too. There was a time when $20 a month went a lot further with me than it does now.
Also remember that purchasing content or shows, while appreciated does not automatically come with free communication. Huge pet peeve is when someone says "I bought a video to support you" and I'm like .. no you bought a video to jerk off. If you want to support me/pay for my attention, the best way to do that is a tip!
If it's something public like twitter or instagram - read their rules, follow their lead. And obv be tipping if you expect engagement.
If it's something you bought, like snapchat - I think its really important to check what to expect up front.
Real world examples:
My snapchat used to be $15 a month and I would post around 40-60 snaps a day to my story, send extras to my clubs who had spent $300+ and respond to people based on how much they were tipping recently. Everyone got responses daily but I prioritized it. Dirty talk / sexy talk was extra.
Now my snapchat is $50 for lifetime and I promise very little. Occasional snaps to my story with no pressure to post, and the ability to message me. I will respond when I can. This will still heavily depend on my relationship with the person and their spending.
Fella #1: There's a fella on my snap who has been around from MFC days. He used to tip well on mfc but has not chosen to engage in the other platforms I now work on (clips and subscription sites). Every single time he contacts me on snap he's whining about how he misses me. I have sent him multiple ways he can see me - calls, private sessions, sexting, customs, OF/Fansly etc. He just says "yeah i know babe" and does none of them. Now I send him emoji responses... lol.
Fella #2: There's another fella on my snap from MFC days. He moved over to OF and will message me on snap as its more convenient for him at work. He sends tips on OF immediately when he gets home for any spicy talk, and everytime he makes contact it's usually regarding a purchase. I respond to him as quick as I'm able. At one point he was sending a LOT of messages on snap and tipping but it seemed like he wasn't sure when and how to tip so I messaged him and told him I really liked our spicy talks, but if he was sending x y and z it needed to come with a tip of x amount and he immediately adjusted his behavior.
Fella #3: There's one other fella on my snap who from time to time cashapps me $50-$100. He messages me on snap to tell me about his dating life. He's patient with slow responses, very sweet, and just easy to talk to. I make sure to respond to him when I see his messages - usually every other day.
Boundaries are really good and if the model isn't making them clear, I'd encourage you to ask. Here's a suggested script I would LOVE to receive!
"hey I really love to chat, but I know I got your snap for a lifetime and there are times I won't be able to contribute every month. What level of communication from me here is appropriate on a month where I am not able to tip?"
I also think that taking a hint is a good idea. If she's gone quiet and isn't taking time off, send a tip see if she becomes more responsive. If she's only responding in emojis or likes, and you tip her $10 and she suddenly talks to you again, that's a good gauge.
All the other ways to find out when a model is online, and you refuse to do that because you expect the model to reach out to you (so you can try to rope her into endless free chitchat off-cam).
