How often do you get downtime to craft, learn new tools/languages, etc.?

[Greywander]

I know this will vary widely from campaign to campaign, and table to table, I'm just curious what typical trends are. I've been looking at artificer builds, and with Tool Expertise it would be useful to get as many tool proficiencies as possible. In fact, I'm considering making it a personal goal of the character to master every tool. As per Xanathar's rules, it costs 25 gp a week and takes 10 weeks minus your INT mod, so with an INT of 20 I could learn a new tool in 5 weeks at a cost of 125 gp. For learning them earlier, it's unlikely I'll have the disposable cash to get anything at levels 1 to 3, so with an 18 INT it would take 6 weeks and cost 150 gp. It's also not clear if training requires consecutive weeks, or if you can do a week here and a week there.

This isn't just for artificers, either, it would apply to pretty much any character who has the extra cash and could use another language or tool proficiency, or might want to craft an item, or perform some other downtime task. Is it common to get a few weeks of downtime between adventures, or do most tables move pretty fast?

[Jerrykhor]

I have seen most campaigns do have 1 to 3 downtime periods, ranging anywhere from 2 weeks to 1 year. Generally, the more sandbox-y style tend to have more downtimes.

And most DMs dont follow the rules for training skills or tools.